Marin Transit is a public bus agency in Marin County, California, in the United States. Originally formed in 1964 as Marin County Transit District (MCTD). Marin Transit was re-branded on 30 July 2007 and now provides a variety of fixed-route and demand-response services using contractors. In 2023, the system had a ridership of 2,814,700, or about 8,800 per weekday as of the fourth quarter of 2023.