On 1 July 1976, San Mateo County Transit District (commonly known as SamTrans) started operations after being created by State Legislature and backed by voters. This district was formed by the union of eleven different bus operators in San Mateo County.
San Mateo County Transit District also oversees Caltrain operations, which provides commuter rail service between San Francisco and Gilroy in southern Santa Clara County, and the San Mateo County Transportation Authority. And it has been instrumental in providing bus service prior to BART arriving in San Mateo County for years, with services around Daly City, South San Francisco, San Bruno, and Millbrae.
On 10 September 2016, SamTrans commemorated its 40th anniversary in service by giving transit fans an open house party at the San Mateo County Events Center. It attracted hundreds of people, from transit operators to regular riders. The event had indoor and outdoor exhibitions, a Roadeo showcase, food trucks, and more.