| County seat|| Oakland|
| Supervisors|| Scott Haggerty|
| Transit Systems|| AC Transit|
| Official website: www.co.alameda.ca.us |
Located across the Bay Bridge from San Francisco, Alameda County was formed on March 25, 1853, and incorporated on June 6th of that year. The county name is derived from alamo the Spanish name for the poplar tree, and means a "grove of poplar trees."