AC Transit (
Alameda-Contra Costa Transit District) is an
Oakland-based public transit agency serving the western portions of
Alameda and
Contra Costa counties in the
East Bay portion of the
San Francisco Bay Area. AC Transit also operates "Transbay" routes across
San Francisco Bay to
San Francisco and selected areas in
San Mateo and
Santa Clara counties. AC Transit is constituted as a
special district under California law. It is governed by seven elected members (five from geographic wards and two at large). It is not a part of or under the control of Alameda or Contra Costa counties or any local jurisdictions.