Prior to the legislative act approving the creation of a Board of Supervisors in 1855, county matters were heard in regularly held "Courts of Sessions" with the County Judge presiding. Also in attendance were the County Clerk, the Sheriff and the District Attorney. The first "Court of Sessions" was held in June, 1853, at the first county seat in Alvarado (Alvarado later became part of Union City).
The first supervisors were appointed and the first meeting of the Board of Supervisors was held in the San Leandro Courthouse on April 2, 1855.
Select the following links to view a list of all Alameda County Supervisors from 1855 - present. The information listed was derived from Minute Records, notes, and County memos. Redistricting has taken place in the following years: 1873, 1885, 1897, 1955, 1965, 1971, 1975, 1981 and within one year of the completion of the Census thereafter. District numbers/areas have been noted, if known.