The Office of the Medical Reserve Corps (MRC) is a national network of 300,000 volunteers organized into approximately 750 local community-based groups which are committed to improving local emergency response capabilities, reducing vulnerabilities, and building community preparedness and resilience. MRC units organize and utilize local volunteers who want to donate their time and expertise to prepare for and respond to emergencies and to support steady-state preparedness initiatives. MRC volunteers include medical and public health professionals as well as other community members without healthcare backgrounds. MRC units bolster their community's preparedness and emergency response infrastructures by providing supplemental personnel when needed, thus making those local communities less likely to be reliant on state and national resources. The majority of MRC units are sponsored by local health departments; other types of sponsoring organizations include emergency management agencies, local non-profits, and universities.