History of Alameda County Districts
History of Alameda County, California, 1883, by M. W. Wood
Washington (The Centennial Year Book of Alameda County, California Biographical Sketches - Prominent Pioneers and Public Men, Oakland, California, Published by William Halley, 1876)
Formation of Alameda County
Oakland township was incorporated in 1852 with possibly a hundred voters. Names of places like Alameda, Brooklyn, Peraltas, Clinton, San Antonia, San Lorenzo, Hayward, Mount Eden, New Haven, Centerville, Corners, Mission, Warm Springs, Sunol, Alisal (Pleasanton), and Mountain House as well as sirnames Castro, Amdor, and Livermore showed up in early days and some of them survived as district and city names.
On March 25, 1853, an Act of Incorporation was created and Alameda County was "born". Created from parts of Contra Costa and Santa Clara Counties, the act was signed into law by Governor Bigler on April 6, 1853.
The Spanish word alameda means "a place where poplar trees grow," a name which originally was given to the Arroyo de la Alameda (Poplar Grove Creek). The willow and sycamore trees along the banks of the river reminded the early explorers of a road lined with trees, also known as an alameda.
The old Court of Sessions managed the affairs of the county at first, performing the functions later conferred upon the board of supervisors when created. The first term of the Court was held at the county seat, Alvarado, June 5, 1853. They proceeded to divide the county into six townships, namely: Contra Costa, Clinton, Eden, Washington, Oakland, and Murray. These divisions remained only until December 12 of that year, when they were re-bounded and reduced to five, namely: Oakland, Clinton, Eden, Washington and Murray. On January 5, 1878, they were again changed to six- Alameda, Brooklyn, Eden, Murray, Oakland and Washington.
Formation of Board of supervisors
The board was created in 1855 by the CA legislative act. 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.
The county seat at the time it was formed in 1853 was located at Alvarado; it was moved to San Leandro in 1856 wherethe county courthouse was destroyed by the devastating 1868 quake on the Hayward Fault. The county seat was then re-established in the town of Brooklyn from 1872-1875. Brooklyn is now part of Oakland, which has been the county seat since 1873.
Much of what is now considered an intensively urban region, with major cities, was developed as a trolley car suburb of San Francisco in the late 19th and early 20th centuries. The historical progression from native American tribal lands to Spanish, then Mexican ranches, then to farms, ranches, and orchards, then multiple city centers and suburbs, is shared with the adjacent and closely associated Contra Costa County.
References: History of Alameda County, California, 1883, by M. W. Wood; Wikipedia Alameda County and Alameda County Board of Supervisors; Alameda County History; Alameda County CAGenWeb