High Quality Content by WIKIPEDIA articles! SamTrans (stylized as samTrans; officially the San Mateo County Transit District) is a public transport agency in and around San Mateo, California, in the San Francisco Bay Area. It provides bus service throughout San Mateo County and into portions of San Francisco and Palo Alto. Service is largely concentrated on the Bay side of the San Bruno Mountains, leaving coast-side service south of Pacifica spotty and intermittent.