Due to the rapidly expanding nature of Californias population, Marins congressional district has changed numerous times over the decades. The county has been part of the Californias 2nd congressional district of California since 2012; the only other time it was part of the 2nd district was 1902–12. It has also been part of the Californias 1st congressional district (1894–1902 and 1912–66), Californias 3rd congressional district (1864–94), Californias 5th congressional district (1974–82), and the Californias 6th congressional district (1972–74 and 1982–2012). The only time the county has not been in a single congressional district was between 1966 and 1972, when it was divided between the northern half in the 1st district and the southern half in the 6th district.. Which congressional districts has Marin been a part of only one time?