Top 100 Contractors in NAICS 541620: Environmental Consulting Services, Jul 2025–Jun 2026

Name: Top 100 Contractors in NAICS 541620: Environmental Consulting Services, Jul 2025–Jun 2026
Creator: GovTribe

Parent companies by net contract obligations Jul 1, 2025 – Jun 30, 2026 Code page on GovTribe

The top 10 won 31% of NAICS 541620 contract dollars from July 2025 through June 2026

Contract obligations: $1,060,494,242 Net of deobligations, by contracts coded NAICS 541620
Contractors: 735 Parent companies with an obligation
Largest contractor: Tetra Tech, Inc. $61.2 million, 4.9% of obligations
Data as of: Oct 16, 2026

Contract actions from FPDS (SAM.gov). How the rankings work · Download all 100 rows as CSV

Full ranking

Rank	Contractor	Net obligations	Share	Trend
1	Tetra Tech, Inc. 13 awardees, including Bridgenet International Inc. Top agencies EPA (Environmental Protection Agency) NASA (National Aeronautics and Space Administration) DOE (Department of Energy)	$61,203,803	4.9%	Rank history: #1 in FY2021, #1 in FY2022, #1 in FY2023, #2 in FY2024 and #1 in FY2025; unchanged since Jul 2024–Jun 2025.
2	Eastern Research Group Inc. Top agencies EPA (Environmental Protection Agency) DOI (Department of the Interior) DOL (Department of Labor)	$54,337,443	4.3%	Rank history: #3 in FY2021, #2 in FY2022, #2 in FY2023, #1 in FY2024 and #3 in FY2025; unchanged since Jul 2024–Jun 2025.
3	Vernadero Group Inc. Top agencies DHS (Department of Homeland Security) Army (Department of the Army) USAF (Department of the Air Force)	$48,502,604	3.9%	Rank history: not on the FY2021–FY2023 lists, #63 in FY2024 and #17 in FY2025; up 48 since Jul 2024–Jun 2025.
4	Gulf South Research Corp Top agencies DHS (Department of Homeland Security) Army (Department of the Army) USAF (Department of the Air Force)	$42,047,578	3.4%	Rank history: not on the FY2021–FY2024 lists and #7 in FY2025; up 206 since Jul 2024–Jun 2025.
5	Weston Solutions Holdings Inc 4 awardees, including Weston Solutions Inc. Top agencies EPA (Environmental Protection Agency) DOT (Department of Transportation)	$39,422,631	3.1%	Rank history: #6 in FY2021, #6 in FY2022, #6 in FY2023, #6 in FY2024 and #2 in FY2025; down 2 since Jul 2024–Jun 2025.
6	Project Enhancement Corporation Top agencies DOE (Department of Energy)	$32,512,464	2.6%	Rank history: #4 in FY2021, #4 in FY2022, #3 in FY2023, #4 in FY2024 and #4 in FY2025; down 2 since Jul 2024–Jun 2025.
7	General Dynamics Corporation 2 awardees, including General Dynamics Information Technology, Inc. Top agencies EPA (Environmental Protection Agency)	$31,432,492	2.5%	Rank history: #32 in FY2021, not on the FY2022 list, #37 in FY2023, #7 in FY2024 and #9 in FY2025; up 14 since Jul 2024–Jun 2025.
8	Lynker Corporation Top agencies Commerce (Department of Commerce)	$29,412,995	2.3%	Rank history: #15 in FY2021, #9 in FY2022, #8 in FY2023, #8 in FY2024 and #5 in FY2025; down 2 since Jul 2024–Jun 2025.
9	S C & A Inc. Top agencies EPA (Environmental Protection Agency) DOI (Department of the Interior) DOE (Department of Energy)	$28,403,335	2.3%	Rank history: #48 in FY2021, #47 in FY2022, #33 in FY2023, #5 in FY2024 and #6 in FY2025; down 2 since Jul 2024–Jun 2025.
10	Tierra Right of Way Services Ltd Top agencies DHS (Department of Homeland Security) DOI (Department of the Interior)	$22,982,826	1.8%	Rank history: not on the FY2021–FY2025 lists; new, not ranked in Jul 2024–Jun 2025.
11	ECO & Associates, Inc. Top agencies DHS (Department of Homeland Security) Army (Department of the Army) DOI (Department of the Interior)	$17,784,772	1.4%	Rank history: #17 in FY2021, #21 in FY2022, not on the FY2023–FY2024 lists and #73 in FY2025; up 157 since Jul 2024–Jun 2025.
12	Environmental Compliance Consultants, Inc. Top agencies Army (Department of the Army) USAF (Department of the Air Force) Navy (Department of the Navy)	$15,380,316	1.2%	Rank history: not on the FY2021–FY2023 lists, #69 in FY2024 and #15 in FY2025; up 43 since Jul 2024–Jun 2025.
13	Rpi-Css, LLC Top agencies Commerce (Department of Commerce)	$15,315,627	1.2%	Rank history: not on the FY2021–FY2024 lists and #8 in FY2025; new, not ranked in Jul 2024–Jun 2025.
14	Gryphon Environmental, LLC Top agencies Army (Department of the Army) Navy (Department of the Navy) USAF (Department of the Air Force)	$14,956,616	1.2%	Rank history: #22 in FY2021, #16 in FY2022, #19 in FY2023, #17 in FY2024 and #12 in FY2025; up 1 since Jul 2024–Jun 2025.
15	The Solution Foundry, LLC Top agencies Army (Department of the Army) USAF (Department of the Air Force)	$13,774,070	1.1%	Rank history: #24 in FY2021, #14 in FY2022, #24 in FY2023, #18 in FY2024 and #14 in FY2025; up 3 since Jul 2024–Jun 2025.
16	Jacobs Geosyntec A Joint Venture Top agencies NASA (National Aeronautics and Space Administration)	$13,162,002	1.0%	Rank history: not on the FY2021–FY2024 lists and #11 in FY2025; up 82 since Jul 2024–Jun 2025.
17	The Cadmus Group LLC Top agencies EPA (Environmental Protection Agency) HHS (Department of Health and Human Services)	$13,032,581	1.0%	Rank history: not on the FY2021 list, #17 in FY2022, #4 in FY2023, #3 in FY2024 and #19 in FY2025; down 12 since Jul 2024–Jun 2025.
18	Marstel-Day, LLC Top agencies Navy (Department of the Navy) DOI (Department of the Interior) USAF (Department of the Air Force)	$13,016,628	1.0%	Rank history: not on the FY2021 list, #41 in FY2022, #17 in FY2023, #20 in FY2024 and #23 in FY2025; up 42 since Jul 2024–Jun 2025.
19	Sundance Consultants, LLC 2 awardees, including Sundance EA Associates II Top agencies DHS (Department of Homeland Security) Navy (Department of the Navy) DOI (Department of the Interior)	$12,676,662	1.0%	Rank history: not on the FY2021 list, #89 in FY2022, #21 in FY2023, #41 in FY2024 and #52 in FY2025; up 21 since Jul 2024–Jun 2025.
20	Bluestone Environmental Group, Inc. Top agencies Army (Department of the Army) NASA (National Aeronautics and Space Administration) USDA (Department of Agriculture)	$12,364,651	1.0%	Rank history: #86 in FY2021, #48 in FY2022, #36 in FY2023, #24 in FY2024 and #16 in FY2025; up 5 since Jul 2024–Jun 2025.
21	Independent Strategic Management Solutions Inc Top agencies DOE (Department of Energy)	$10,142,173	0.8%	Rank history: not on the FY2021–FY2023 lists, #44 in FY2024 and #24 in FY2025; up 5 since Jul 2024–Jun 2025.
22	Weston-Techlaw JV LLC Top agencies EPA (Environmental Protection Agency)	$9,685,736	0.8%	Rank history: not on the FY2021 list, #30 in FY2022, #14 in FY2023, #16 in FY2024 and #20 in FY2025; down 9 since Jul 2024–Jun 2025.
23	WSP USA Solutions Inc 2 awardees, including WSP Italia S.R.L. Top agencies DOE (Department of Energy) GSA (General Services Administration) DOT (Department of Transportation)	$8,987,061	0.7%	Rank history: not on the FY2021–FY2023 lists, #13 in FY2024 and #25 in FY2025; down 12 since Jul 2024–Jun 2025.
24	Research Planning, Inc. Top agencies Commerce (Department of Commerce) DHS (Department of Homeland Security)	$8,615,009	0.7%	Rank history: not on the FY2021–FY2023 lists, #54 in FY2024 and #77 in FY2025; up 48 since Jul 2024–Jun 2025.
25	WSP USA Environment & Infrastructure Inc. Top agencies EPA (Environmental Protection Agency) DOI (Department of the Interior)	$8,420,251	0.7%	Rank history: not on the FY2021–FY2023 lists, #58 in FY2024 and #13 in FY2025; down 3 since Jul 2024–Jun 2025.
26	Chenega Reliable Services LLC Top agencies USAF (Department of the Air Force) Army (Department of the Army)	$8,393,604	0.7%	Rank history: not on the FY2021–FY2023 lists, #26 in FY2024 and #26 in FY2025; down 6 since Jul 2024–Jun 2025.
27	Environmental Management Support, Inc. Top agencies EPA (Environmental Protection Agency)	$7,599,677	0.6%	Rank history: #69 in FY2021, #96 in FY2022, #77 in FY2023, #75 in FY2024 and #56 in FY2025; up 162 since Jul 2024–Jun 2025.
28	Dawson Mcg, Inc. Top agencies DHS (Department of Homeland Security) Army (Department of the Army)	$6,953,605	0.6%	Rank history: not on the FY2021–FY2024 lists and #30 in FY2025; up 89 since Jul 2024–Jun 2025.
29	DR Reed & Associates, Inc. Top agencies DOI (Department of the Interior)	$6,911,993	0.6%	Rank history: not on the FY2021–FY2024 lists and #28 in FY2025; new, not ranked in Jul 2024–Jun 2025.
30	Alpha Facilities Solutions LLC Top agencies DODEA (Department of Defense Education Activity) USDA (Department of Agriculture) Army (Department of the Army)	$6,908,635	0.6%	Rank history: not on the FY2021–FY2024 lists and #97 in FY2025; up 86 since Jul 2024–Jun 2025.
31	Hsg, LLC Top agencies NASA (National Aeronautics and Space Administration) USAF (Department of the Air Force) DOI (Department of the Interior)	$6,907,774	0.6%	Rank history: #50 in FY2021, #40 in FY2022, #53 in FY2023, #36 in FY2024 and #21 in FY2025; down 3 since Jul 2024–Jun 2025.
32	Signature Science, LLC Top agencies DFAS (Defense Finance and Accounting Service) DHS (Department of Homeland Security) Army (Department of the Army)	$6,802,921	0.5%	Rank history: not on the FY2021–FY2023 lists, #52 in FY2024 and #33 in FY2025; up 12 since Jul 2024–Jun 2025.
33	Great Lakes Environmental Center, Inc. Top agencies EPA (Environmental Protection Agency) Army (Department of the Army) USDA (Department of Agriculture)	$6,772,552	0.5%	Rank history: #60 in FY2021, #24 in FY2022, #23 in FY2023, #21 in FY2024 and #37 in FY2025; down 10 since Jul 2024–Jun 2025.
34	GV Henson Creek LLC Top agencies DHS (Department of Homeland Security)	$6,658,663	0.5%	Rank history: not on the FY2021–FY2024 lists and #32 in FY2025; new, not ranked in Jul 2024–Jun 2025.
35	Osage Nation Energy Services LLC Top agencies Army (Department of the Army)	$6,634,205	0.5%	Rank history: not on the FY2021–FY2025 lists; new, not ranked in Jul 2024–Jun 2025.
36	Stantec Inc. 3 awardees, including Stantec Consulting Services Inc. and Stantec GS Inc. Top agencies DOI (Department of the Interior) GSA (General Services Administration) DHS (Department of Homeland Security)	$6,510,782	0.5%	Rank history: not on the FY2021–FY2022 lists, #60 in FY2023, not on the FY2024 list and #27 in FY2025; up 55 since Jul 2024–Jun 2025.
37	SRC Inc. Top agencies EPA (Environmental Protection Agency) HHS (Department of Health and Human Services)	$6,391,764	0.5%	Rank history: #23 in FY2021, #23 in FY2022, #32 in FY2023, #29 in FY2024 and #75 in FY2025; up 6 since Jul 2024–Jun 2025.
38	SOL Solutions LLC Top agencies Army (Department of the Army) Navy (Department of the Navy)	$6,376,205	0.5%	Rank history: not on the FY2021–FY2023 lists, #15 in FY2024 and #39 in FY2025; down 9 since Jul 2024–Jun 2025.
39	Ciri Development Corporation Through North Wind Resource Consulting LLC Top agencies DOI (Department of the Interior) Army (Department of the Army) USDA (Department of Agriculture)	$6,271,133	0.5%	Rank history: not on the FY2021–FY2022 lists, #34 in FY2023, #100 in FY2024 and #36 in FY2025; up 67 since Jul 2024–Jun 2025.
40	Environmental Assessment Services, LLC Top agencies Army (Department of the Army) USDA (Department of Agriculture) USAF (Department of the Air Force)	$5,935,943	0.5%	Rank history: not on the FY2021–FY2023 lists, #49 in FY2024 and #10 in FY2025; down 26 since Jul 2024–Jun 2025.
41	Neptune and Company, Incorporated Top agencies DOE (Department of Energy) EPA (Environmental Protection Agency) HHS (Department of Health and Human Services)	$5,537,611	0.4%	Rank history: not on the FY2021–FY2022 lists, #58 in FY2023, #70 in FY2024 and #46 in FY2025; up 20 since Jul 2024–Jun 2025.
42	Environmental Research Group LLC Top agencies Army (Department of the Army) WHS (DOD Washington Headquarters Service) Navy (Department of the Navy)	$5,521,705	0.4%	Rank history: not on the FY2021–FY2022 lists, #38 in FY2023, #43 in FY2024 and #66 in FY2025; up 27 since Jul 2024–Jun 2025.
43	Jacobs Engineering Group Inc. Top agencies Army (Department of the Army)	$5,465,983	0.4%	Rank history: not on the FY2021–FY2023 lists, #53 in FY2024 and #41 in FY2025; up 6 since Jul 2024–Jun 2025.
44	Tehama ECS LLC Top agencies Army (Department of the Army) USAF (Department of the Air Force) DOI (Department of the Interior)	$5,449,484	0.4%	Rank history: not on the FY2021–FY2024 lists and #51 in FY2025; up 38 since Jul 2024–Jun 2025.
45	Aerostar Environmental and Construction LLC Top agencies Army (Department of the Army)	$5,438,184	0.4%	Rank history: not on the FY2021 list, #49 in FY2022, #35 in FY2023, #37 in FY2024 and #31 in FY2025; down 3 since Jul 2024–Jun 2025.
46	Mabbett & Associates, Inc. Top agencies VA (Department of Veterans Affairs) GSA (General Services Administration) Army (Department of the Army)	$5,231,164	0.4%	Rank history: #37 in FY2021, #39 in FY2022, #39 in FY2023, #27 in FY2024 and #50 in FY2025; down 1 since Jul 2024–Jun 2025.
47	Genwest Systems Inc. Top agencies Commerce (Department of Commerce)	$5,120,634	0.4%	Rank history: #25 in FY2021, #25 in FY2022, #41 in FY2023, #95 in FY2024 and #43 in FY2025; up 17 since Jul 2024–Jun 2025.
48	Aleut Technical Services, LLC Top agencies EPA (Environmental Protection Agency)	$4,800,848	0.4%	Rank history: not on the FY2021–FY2022 lists, #100 in FY2023, #71 in FY2024 and #96 in FY2025; up 38 since Jul 2024–Jun 2025.
49	Toeroek Associates, Inc. Top agencies EPA (Environmental Protection Agency)	$4,761,753	0.4%	Rank history: #56 in FY2021, #18 in FY2022, #29 in FY2023, #87 in FY2024 and #84 in FY2025; up 39 since Jul 2024–Jun 2025.
50	Dgi-Ati II LLC Top agencies WHS (DOD Washington Headquarters Service) Army (Department of the Army)	$4,704,329	0.4%	Rank history: not on the FY2021–FY2024 lists and #58 in FY2025; up 3 since Jul 2024–Jun 2025.
51	Copperhead Environmental Consulting Inc. Top agencies DOI (Department of the Interior) USDA (Department of Agriculture)	$4,654,552	0.4%	Rank history: not on the FY2021–FY2024 lists and #38 in FY2025; new, not ranked in Jul 2024–Jun 2025.
52	Association of Consultants and Engineers Top agencies Navy (Department of the Navy) MDA (DOD Missile Defense Agency)	$4,627,206	0.4%	Rank history: #44 in FY2021, #61 in FY2022, #31 in FY2023, #65 in FY2024 and #70 in FY2025; up 16 since Jul 2024–Jun 2025.
53	AECOM 3 awardees, including Environmental Management & Planning Solutions LLC, AECOM Services, LLC and AECOM Italia S.P.A. Top agencies DOI (Department of the Interior) EOP (Executive Office of the President) Army (Department of the Army)	$4,623,611	0.4%	Rank history: #20 in FY2021, #22 in FY2022, #26 in FY2023, #31 in FY2024 and not on the FY2025 list; down 22 since Jul 2024–Jun 2025.
54	Hydrogeologic, Inc. Top agencies NASA (National Aeronautics and Space Administration)	$4,540,141	0.4%	Rank history: #98 in FY2021, not on the FY2022 list, #71 in FY2023 and not on the FY2024–FY2025 lists; up 81 since Jul 2024–Jun 2025.
55	LMI Consulting, LLC Top agencies DHS (Department of Homeland Security)	$4,482,388	0.4%	Rank history: not on the FY2021–FY2024 lists and #60 in FY2025; new, not ranked in Jul 2024–Jun 2025.
56	Property & Environmental Management Inc. Top agencies HHS (Department of Health and Human Services)	$4,280,855	0.3%	Rank history: not on the FY2021–FY2023 lists, #45 in FY2024 and #88 in FY2025; up 68 since Jul 2024–Jun 2025.
57	Haztrain Inc. Top agencies USAF (Department of the Air Force) EPA (Environmental Protection Agency)	$4,161,676	0.3%	Rank history: not on the FY2021–FY2023 lists, #67 in FY2024 and #48 in FY2025; down 20 since Jul 2024–Jun 2025.
58	ICF International Inc. 2 awardees, including ICF Incorporated, L.L.C. and ICF Environmental, Inc. Top agencies EPA (Environmental Protection Agency) DOT (Department of Transportation) DOI (Department of the Interior)	$4,147,839	0.3%	Rank history: not on the FY2021–FY2023 lists, #22 in FY2024 and #35 in FY2025; down 23 since Jul 2024–Jun 2025.
59	Bluestone - Burns & Mcdonnell JV Top agencies EPA (Environmental Protection Agency) Army (Department of the Army)	$4,032,452	0.3%	Rank history: not on the FY2021–FY2025 lists; up 221 since Jul 2024–Jun 2025.
60	Skeo Solutions, Inc. Top agencies EPA (Environmental Protection Agency)	$4,013,278	0.3%	Rank history: #70 in FY2021, #10 in FY2022, #16 in FY2023, #14 in FY2024 and #57 in FY2025; down 36 since Jul 2024–Jun 2025.
61	Trinity Analysis and Development Corp. Top agencies USAF (Department of the Air Force)	$3,889,114	0.3%	Rank history: not on the FY2021–FY2024 lists and #83 in FY2025; up 70 since Jul 2024–Jun 2025.
62	Cherokee Federal Solutions, L.L.C. Top agencies Army (Department of the Army)	$3,733,221	0.3%	Rank history: not on the FY2021–FY2023 lists, #97 in FY2024 and #68 in FY2025; up 23 since Jul 2024–Jun 2025.
63	Earth Resources Technology, LLC Top agencies Commerce (Department of Commerce)	$3,636,487	0.3%	Rank history: not on the FY2021–FY2022 lists, #73 in FY2023, not on the FY2024 list and #63 in FY2025; up 15 since Jul 2024–Jun 2025.
64	Paleowest LLC Top agencies DOI (Department of the Interior) Army (Department of the Army) USDA (Department of Agriculture)	$3,529,564	0.3%	Rank history: #41 in FY2021, #60 in FY2022, not on the FY2023 list, #74 in FY2024 and #72 in FY2025; up 59 since Jul 2024–Jun 2025.
65	Ardl Inc. Top agencies Army (Department of the Army)	$3,525,478	0.3%	Rank history: #9 in FY2021, #99 in FY2022, #46 in FY2023, not on the FY2024 list and #90 in FY2025; up 160 since Jul 2024–Jun 2025.
66	Earth Smart Environmental Solutions LLC Top agencies VA (Department of Veterans Affairs)	$3,462,655	0.3%	Rank history: #100 in FY2021, #98 in FY2022, not on the FY2023 list, #89 in FY2024 and #91 in FY2025; up 13 since Jul 2024–Jun 2025.
67	Rmec Environmental Inc Top agencies Army (Department of the Army) DOI (Department of the Interior)	$3,425,293	0.3%	Rank history: not on the FY2021–FY2022 lists, #98 in FY2023, #91 in FY2024 and #76 in FY2025; up 13 since Jul 2024–Jun 2025.
68	Tahkox E2-Whitetail LLC Top agencies Army (Department of the Army)	$3,380,110	0.3%	Rank history: not on the FY2021–FY2023 lists, #84 in FY2024 and #53 in FY2025; up 7 since Jul 2024–Jun 2025.
69	Melwood Horticultural Training Center, Inc. Top agencies DOJ (Department of Justice)	$3,364,204	0.3%	Rank history: not on the FY2021 list, #95 in FY2022, not on the FY2023–FY2024 lists and #85 in FY2025; up 24 since Jul 2024–Jun 2025.
70	Straughan Environmental, Inc. Top agencies NASA (National Aeronautics and Space Administration)	$3,330,947	0.3%	Rank history: #62 in FY2021, #71 in FY2022, #59 in FY2023, #32 in FY2024 and #64 in FY2025; down 38 since Jul 2024–Jun 2025.
71	Environmental Science Services Inc. Top agencies Army (Department of the Army)	$3,324,853	0.3%	Rank history: not on the FY2021–FY2024 lists and #80 in FY2025; new, not ranked in Jul 2024–Jun 2025.
72	Ayuda Companies Top agencies Navy (Department of the Navy)	$3,254,693	0.3%	Rank history: not on the FY2021–FY2025 lists; new, not ranked in Jul 2024–Jun 2025.
73	Q & A Diversified LLC Top agencies Army (Department of the Army)	$3,053,077	0.2%	Rank history: not on the FY2021–FY2024 lists and #59 in FY2025; up 27 since Jul 2024–Jun 2025.
74	Brice Solutions, LLC Top agencies DHS (Department of Homeland Security) Army (Department of the Army)	$3,038,396	0.2%	Rank history: not on the FY2021–FY2023 lists, #39 in FY2024 and #87 in FY2025; down 44 since Jul 2024–Jun 2025.
75	Ack3 Consulting, LLC Top agencies HHS (Department of Health and Human Services)	$2,998,739	0.2%	Rank history: not on the FY2021–FY2025 lists; up 341 since Jul 2024–Jun 2025.
76	Propel Solutions LLC Top agencies Commerce (Department of Commerce)	$2,924,253	0.2%	Rank history: not on the FY2021–FY2024 lists and #62 in FY2025; up 29 since Jul 2024–Jun 2025.
77	Oneida Environmental, LLC Top agencies Army (Department of the Army) DOI (Department of the Interior) USAF (Department of the Air Force)	$2,920,862	0.2%	Rank history: not on the FY2021–FY2023 lists, #60 in FY2024 and #89 in FY2025; down 27 since Jul 2024–Jun 2025.
78	Renova-Sovereign Joint Venture Top agencies Army (Department of the Army)	$2,791,650	0.2%	Rank history: #45 in FY2021, #59 in FY2022, not on the FY2023–FY2024 lists and #92 in FY2025; up 335 since Jul 2024–Jun 2025.
79	LRS Federal LLC Top agencies DHS (Department of Homeland Security) DOJ (Department of Justice)	$2,732,996	0.2%	Rank history: #30 in FY2021, #85 in FY2022, #27 in FY2023 and not on the FY2024–FY2025 lists; up 34 since Jul 2024–Jun 2025.
80	Nemean Solutions LLC Top agencies Army (Department of the Army)	$2,687,682	0.2%	Rank history: not on the FY2021–FY2025 lists; up 153 since Jul 2024–Jun 2025.
81	Cherokee Nation Government Solutions, L.L.C. Top agencies Army (Department of the Army) USAF (Department of the Air Force)	$2,641,935	0.2%	Rank history: not on the FY2021–FY2025 lists; up 73 since Jul 2024–Jun 2025.
82	First Environment Inc. Top agencies Army (Department of the Army) VA (Department of Veterans Affairs) USAF (Department of the Air Force)	$2,635,860	0.2%	Rank history: #42 in FY2021, not on the FY2022–FY2023 lists, #42 in FY2024 and #86 in FY2025; down 43 since Jul 2024–Jun 2025.
83	Air Resource Specialists, Inc. Top agencies DOI (Department of the Interior) EPA (Environmental Protection Agency)	$2,592,695	0.2%	Rank history: #81 in FY2021, #86 in FY2022, #69 in FY2023, #86 in FY2024 and #98 in FY2025; up 9 since Jul 2024–Jun 2025.
84	Integrated Systems Solutions, Inc. Top agencies Commerce (Department of Commerce)	$2,577,650	0.2%	Rank history: #71 in FY2021, #50 in FY2022, #75 in FY2023, #38 in FY2024 and #44 in FY2025; down 38 since Jul 2024–Jun 2025.
85	Koman ECO Ageiss JV LLC Top agencies USAF (Department of the Air Force) Army (Department of the Army)	$2,570,061	0.2%	Rank history: not on the FY2021–FY2024 lists and #81 in FY2025; down 19 since Jul 2024–Jun 2025.
86	Ocean Associates Inc. Top agencies Commerce (Department of Commerce)	$2,565,756	0.2%	Rank history: #79 in FY2021, #63 in FY2022, #82 in FY2023, #34 in FY2024 and #47 in FY2025; down 50 since Jul 2024–Jun 2025.
87	Pb&A / CSS JV, Llc. Top agencies EPA (Environmental Protection Agency)	$2,504,319	0.2%	Rank history: not on the FY2021 list, #31 in FY2022, #42 in FY2023 and not on the FY2024–FY2025 lists; up 78 since Jul 2024–Jun 2025.
88	The NDN Companies Top agencies Army (Department of the Army) DOT (Department of Transportation) EPA (Environmental Protection Agency)	$2,488,501	0.2%	Rank history: not on the FY2021–FY2025 lists; up 46 since Jul 2024–Jun 2025.
89	S.s. Papadopulos & Associates, Inc. Top agencies EPA (Environmental Protection Agency) GSA (General Services Administration)	$2,473,933	0.2%	Rank history: #92 in FY2021, #76 in FY2022 and not on the FY2023–FY2025 lists; up 54 since Jul 2024–Jun 2025.
90	Southeastern Archaeological Research LLC Top agencies Army (Department of the Army)	$2,469,182	0.2%	Rank history: not on the FY2021–FY2024 lists and #71 in FY2025; up 17 since Jul 2024–Jun 2025.
91	Solv LLC Top agencies DHS (Department of Homeland Security) DOJ (Department of Justice) DOI (Department of the Interior)	$2,441,971	0.2%	Rank history: #68 in FY2021, #52 in FY2022, #9 in FY2023, #55 in FY2024 and not on the FY2025 list; new, not ranked in Jul 2024–Jun 2025.
92	AECOM Technical Services, Inc. Top agencies NASA (National Aeronautics and Space Administration) Commerce (Department of Commerce) DOI (Department of the Interior)	$2,428,032	0.2%	Rank history: not on the FY2021–FY2023 lists, #35 in FY2024 and #61 in FY2025; down 59 since Jul 2024–Jun 2025.
93	Spatial Front Inc Top agencies Commerce (Department of Commerce)	$2,376,384	0.2%	Rank history: not on the FY2021–FY2022 lists, #70 in FY2023, #85 in FY2024 and #94 in FY2025; down 19 since Jul 2024–Jun 2025.
94	Ahtna Solutions, LLC Top agencies Commerce (Department of Commerce) USAF (Department of the Air Force) Army (Department of the Army)	$2,362,452	0.2%	Rank history: not on the FY2021–FY2023 lists, #56 in FY2024 and #65 in FY2025; down 56 since Jul 2024–Jun 2025.
95	Environmental Science Corporation Top agencies Army (Department of the Army) Navy (Department of the Navy)	$2,289,142	0.2%	Rank history: #67 in FY2021, not on the FY2022–FY2023 lists, #90 in FY2024 and not on the FY2025 list; down 6 since Jul 2024–Jun 2025.
96	Technical Resources Group Inc. Top agencies DOE (Department of Energy)	$2,226,908	0.2%	Rank history: not on the FY2021–FY2025 lists; up 46 since Jul 2024–Jun 2025.
97	Whitetail Environmental, LLC Top agencies Army (Department of the Army) DOI (Department of the Interior)	$2,145,399	0.2%	Rank history: #91 in FY2021, #37 in FY2022, #40 in FY2023, #40 in FY2024 and #99 in FY2025; up 7 since Jul 2024–Jun 2025.
98	Environmental Synectics, Inc. Top agencies Army (Department of the Army)	$2,142,821	0.2%	Rank history: not on the FY2021–FY2025 lists; up 64 since Jul 2024–Jun 2025.
99	Swca Incorporated Top agencies DOI (Department of the Interior)	$2,105,050	0.2%	Rank history: not on the FY2021–FY2025 lists; up 53 since Jul 2024–Jun 2025.
100	Hydros Consulting Inc. Top agencies DOI (Department of the Interior)	$2,048,181	0.2%	Rank history: not on the FY2021–FY2025 lists; up 202 since Jul 2024–Jun 2025.

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100 of 735 contractors listed here. See the rest on GovTribe.

How this ranking works

Source: every contract action FPDS records (as published on SAM.gov) in the period, as GovTribe received it.
Amounts are net obligations: what was obligated, less what was deobligated. Shares are of $1.25 billion obligated before deobligations, so they never pass 100%.
Parent companies: each action counts under the ultimate parent its award record names, or under the awardee when it names none, so no dollar counts twice. Parents of the same name (Inc., LLC and the like aside) count as one company, since FPDS records a company's parent under more than one UEI over time. GovTribe corrects a few parents and names by hand; see the corrections.
Period: the trailing 12 months end with the last month that ended at least 90 days ago, because the Department of Defense reports its contract actions to FPDS about 90 days late. The list is rebuilt each night.
Rank changes compare with Jul 2024–Jun 2025. "New" marks a company outside that period's top 500, and "Returned" one of those that was on an earlier fiscal year's list.
Rank lines show each company's rank on every fiscal year's list since FY2021, #1 at the top, on a scale that gives the top of the list more room. A dashed stretch spans years it wasn't on the list.
Placeholder recipients FPDS uses when it names no company ("Miscellaneous Foreign Contractors" and the like) aren't ranked.

Quick answers

Who were the top 10 NAICS 541620 contractors in Jul 2025–Jun 2026?

1. Tetra Tech, Inc. ($61.2M), 2. Eastern Research Group Inc. ($54.3M), 3. Vernadero Group Inc. ($48.5M), 4. Gulf South Research Corp ($42M), 5. Weston Solutions Holdings Inc ($39.4M), 6. Project Enhancement Corporation ($32.5M), 7. General Dynamics Corporation ($31.4M), 8. Lynker Corporation ($29.4M), 9. S C & A Inc. ($28.4M), 10. Tierra Right of Way Services Ltd ($23M).

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