Alameda County, California

Alameda County (/ˌæləˈmdə/ AL-ə-MEE-də) is a county in the state of California in the United States. As of the 2010 census, the population was 1,510,271,[5] making it the 7th-most populous county in the state.[6] The county seat is Oakland.[7] Alameda County is included in the San Francisco Bay Area, occupying much of the East Bay region.

Alameda County
County of Alameda
Images, from top down, left to right: Looking southwest across Lake Merritt in Oakland, Sather Tower on the UC Berkeley campus, a water tower in Hayward, Lake Elizabeth in Fremont, Pleasanton sign


Location within the state of California
California's location within the United States
Country United States
State California
RegionSan Francisco Bay Area
IncorporatedMarch 25, 1853[1]
Named forRancho Arroyo de la Alameda (also see Alameda Creek)
County seatOakland
Largest cityOakland
  BodyAlameda County Board of Supervisors
  Total821 sq mi (2,130 km2)
  Land739 sq mi (1,910 km2)
  Water82 sq mi (210 km2)
Highest elevation3,843 ft (1,171 m)
  Density1,800/sq mi (710/km2)
Time zoneUTC-8 (Pacific Time Zone)
  Summer (DST)UTC-7 (Pacific Daylight Time)
Area codes510, 925
FIPS code06-001

The Spanish word alameda means either, "...a grove of poplars,...or a tree lined street" a name originally used to describe the Arroyo de la Alameda. The willow and sycamore trees along the banks of the river reminded the early Spanish explorers of a road lined with trees.[8][9] Although a strict translation to English might be "Poplar Grove Creek", the name of the principal stream that flows through the county is now simply "Alameda Creek."

Alameda County is included in the San Francisco–Oakland–Berkeley, CA Metropolitan Statistical Area, which is also included in the San Jose-San Francisco-Oakland, CA Combined Statistical Area.


The county was formed on March 25, 1853, from a large portion of Contra Costa County and a smaller portion of Santa Clara County.

The county seat at the time of the county's formation was located at Alvarado, now part of Union City. In 1856, it was moved to San Leandro, where the 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 to multiple city centers and suburbs, is shared with the adjacent and closely associated Contra Costa County.


The annual county fair is held at the Alameda County Fairgrounds in Pleasanton. The fair runs for four weekends from June to July. Attractions include horse racing, carnival rides, 4-H exhibits, and live bands.


According to the U.S. Census Bureau, the county has a total area of 821 square miles (2,130 km2), of which 739 square miles (1,910 km2) is land and 82 square miles (210 km2) (10%) is water.[10] The San Francisco Bay borders the county on the west.

The crest of the Berkeley Hills form part of the northeastern boundary and reach into the center of the county. A coastal plain several miles wide lines the bay; and is Oakland's most populous region. Livermore Valley lies in the eastern part of the county. Amador Valley abuts the western edge of Livermore Valley and continues west to the Pleasanton Ridge.

The Hayward Fault, a major branch of the San Andreas Fault to the west, runs through the most populated parts of Alameda County, while the Calaveras Fault runs through the southeastern part of the county.

Neighboring counties[11]

The City and County of San Francisco, California, borders the county on the west, and has a small land border with the city of Alameda, California due to land filling.[12]

Santa Clara County borders the county on the south.

San Joaquin County borders the county on the east.

Contra Costa County borders the county on the north.

Stanislaus County borders the county on the eastern-most end of its southern boundary for 250 feet (76 m).

National protected area


A 2014 analysis by The Atlantic found Alameda County to be the fourth most racially diverse county in the United States—behind Aleutians West Census Area and Aleutians East Borough in Alaska, and Queens County in New York—as well as the most diverse county in California.[13]


Places by population, race, and income


Historical population
Est. 20181,666,753[4]</ref>10.4%
U.S. Decennial Census[21]
1790–1960[22] 1900–1990[23]
1990–2000[24] 2010–2015[5]

The 2010 United States Census reported that Alameda County had a population of 1,510,271. The population density was 2,047.6 people per square mile (790.6/km²). The racial makeup of Alameda County was 649,122 (43.0%) White, 190,451 (12.6%) African American, 9,799 (0.6%) Native American, 394,560 (26.1%) Asian (9.7% Chinese, 5.5% Filipino, 4.8% Indian, 2.0% Vietnamese, 1.2% Korean, 0.8% Japanese, 2.2% Other Asian), 12,802 (0.8%) Pacific Islander, 162,540 (10.8%) from other races, and 90,997 (6.0%) from two or more races. Hispanic or Latino of any race were 339,889 persons (22.5%): 16.4% Mexican, 0.8% Puerto Rican, 0.2% Cuban, 5.1% Other Hispanic.[25]


As of the census[27] of 2000, there were 1,443,741 people, 523,366 households, out of which 32.6% had children under the age of 18 living within them, 47.0% married couples living together, 13.0% had a female householder with no husband present, and 35.2% were non-families. 26.0% of all households were made up of individuals and 7.3% had someone living alone who was 65 years of age or older. The average household size was 2.71 and the average family size was 3.31.

In the county, the population was spread out with 24.6% under the age of 18, 9.6% from 18 to 24, 33.9% from 25 to 44, 21.7% from 45 to 64, and 10.2% who were 65 years of age or older. The median age was 34 years. For every 100 females there were 96.60 males. For every 100 females age 18 and over, there were 94.00 males.

The median income for a household in the county was $55,946, and the median income for a family was $65,857 (these figures had risen to $66,430 and $81,341 respectively as of a 2007 estimate[28]). Males had a median income of $47,425 versus $36,921 for females. The per capita income for the county was $26,680. About 7.7% of families and 11.0% of the population were below the poverty line, including 13.5% of those under age 18 and 8.1% of those age 65 or over.

In 2000, the largest denominational group was the Catholics (with 306,437 adherents) .[29] The largest religious bodies were the Catholic Church (with 306,437 members) and Judaism (with 32,500 members).[29]

Law, government and politics


The Government of Alameda County is defined and authorized under the California Constitution, California law, and the Charter of the County of Alameda.[30] Much of the Government of California is in practice the responsibility of county governments such as the Government of Alameda County, while municipalities such as the city of Oakland and the city of Berkeley provide additional, often non-essential services. The County government provides countywide services such as elections and voter registration, law enforcement, jails, vital records, property records, tax collection, and public health. In addition it is the local government for all unincorporated areas, and provides services such as law enforcement to some incorporated cities under a contract arrangement.

It is composed of the elected five-member Alameda County Board of Supervisors (BOS) as the county legislature, several other elected offices and officers including the Sheriff, the District Attorney, Assessor, Auditor-Controller/County Clerk/Recorder, and Treasurer/Tax Collector, and numerous county departments and entities under the supervision of the County Administrator. In addition, several entities of the government of California have jurisdiction conterminous with Alameda County, such as the Alameda County Superior Court.

The current supervisors are:[31]

The Board elects a president who presides at all meetings of the Board and appoints committees to handle work involving the major programs of the county. If the president is absent for a meeting, the vice president shall be responsible. A Board election occurs every two years for these positions. Supervisor Miley is serving currently as president; Supervisor Carson is vice president.

The county's law enforcement is overseen by an elected Sheriff/Coroner and an elected District Attorney. The Sheriff supervises the deputies of the Alameda County Sheriff's Office, whose primary responsibilities include policing unincorporated areas of the county and cities within the county which contract with the Sheriff's Office for police services; providing security and law enforcement for county buildings including courthouses, the county jail and other county properties; providing support resources, such as a forensics laboratory and search and rescue capabilities, to other law enforcement agencies throughout the county; and serving the process of the county's Superior Court system. The District Attorney's office is responsible for prosecuting all criminal violations of the laws of the state of California, the county, or its constituent municipalities, in the Alameda County Superior Court. The current Sheriff is Gregory J. Ahern, who was elected in 2006, succeeding Charles Plummer, who had served in the post for 20 years. The Interim District Attorney is Nancy E. O'Malley, who was appointed to fill the position of retiring District Attorney Tom Orloff in September 2009. The Sheriff's Office operates two jails: Santa Rita Jail in Dublin, and Glenn E. Dyer Detention Facility in downtown Oakland.

The Alameda County Fire Department (ACFD)[32] was formed on July 1, 1993, as a dependent district, with the Board of Supervisors as its governing body. Municipal and specialized fire departments have been consolidated into the ACFD over the years. 1993 brought in the Castro Valley and Eden Consolidated FD, and the County Fire Patrol. San Leandro joined in 1995, Dublin in 1997, Lawrence Berkeley National Laboratory in 2002, Lawrence Livermore National Laboratory in 2007, The Alameda County Regional Emergency Communications Center in 2008, and Newark and Union City in 2010. Emeryville joined the ACFD in 2012.

The Alameda County Water District is a special district within Alameda County created to distribute water, but it is not operated by Alameda County administrators. It is operated by an elected board of directors.

Alameda County Superior Court operates in twelve separate locations throughout the county, with its central René C. Davidson Courthouse located in Oakland near Lake Merritt. Most major criminal trials and complex civil cases are heard at this location or in courtrooms within the County Administration Building across the street.

State and federal representation

In the California State Assembly, Alameda County is split between five districts:

In the California State Senate, the county is split between three districts:

In the United States House of Representatives, the county is split between three districts:


Since 1932, Alameda County has been a stronghold of the Democratic Party, with Dwight Eisenhower being the only Republican presidential nominee to have carried the county since. Prior to 1932, the county had been a Republican stronghold. Piedmont resident William F. Knowland was the Republican U.S. Senate Leader from 1953 to 1959. Even when Ronald Reagan won the national popular vote by an 18.3% margin in 1984, Walter Mondale won Alameda County by a slightly larger margin. In 2004 it voted for John Kerry by a margin of over 75%. Every city and town voted Democratic.[36]

Presidential election results
Alameda County vote
by party in presidential elections
Year GOP DEM Others
2016 14.54% 95,922 78.06% 514,842 7.40% 48,779
2012 18.12% 108,182 78.69% 469,684 3.19% 19,027
2008 19.19% 119,555 78.52% 489,106 2.29% 14,252
2004 23.29% 130,911 75.18% 422,585 1.53% 8,594
2000 24.13% 119,279 69.36% 342,889 6.50% 32,168
1996 23.07% 106,581 65.77% 303,903 11.16% 51,560
1992 20.62% 109,292 63.04% 334,224 16.34% 86,629
1988 33.99% 162,815 64.78% 310,283 1.23% 5,899
1984 40.01% 192,408 58.65% 282,041 1.34% 6,425
1980 37.96% 158,531 48.30% 201,720 13.74% 57,366
1976 38.09% 155,280 57.89% 235,988 4.03% 16,413
1972 42.84% 201,862 55.02% 259,254 2.14% 10,079
1968 37.63% 153,285 53.90% 219,545 8.48% 34,519
1964 33.46% 142,998 66.42% 283,833 0.12% 509
1960 45.61% 183,354 54.02% 217,172 0.37% 1,474
1956 52.40% 192,911 47.27% 174,033 0.32% 1,187
1952 52.69% 201,976 46.50% 178,239 0.80% 3,079
1948 46.57% 150,588 47.80% 154,549 5.63% 18,194
1944 41.83% 122,982 57.70% 169,631 0.47% 1,374
1940 43.56% 116,961 55.21% 148,224 1.23% 3,311
1936 35.09% 82,352 63.63% 149,323 1.28% 3,011
1932 43.68% 89,303 52.04% 106,388 4.29% 8,761
1928 65.42% 118,539 33.60% 60,875 0.98% 1,780
1924 61.48% 81,454 6.05% 8,020 32.46% 43,016
1920 69.11% 73,177 20.27% 21,468 10.62% 11,244
1916 50.34% 51,417 42.84% 43,748 6.82% 6,966
1912 36.75% 24,418 63.26% 42,034
1908 64.24% 21,380 21.36% 7,110 14.40% 4,793
1904 70.32% 19,065 16.23% 4,399 13.45% 3,646
1900 64.64% 14,324 30.13% 6,677 5.23% 1,158
1896 60.43% 13,429 37.77% 8,394 1.80% 400
1892 47.60% 8,792 38.52% 7,114 13.89% 2,564

The California Secretary of State, as of February 2019, reports that there are 883,942 registered voters in Alameda County. 489,759 (55.4%) are registered Democrats, 95,587 (10.8%) are registered Republicans, 36,649 (4.1%) are registered to minor political parties, and 261,947 (29.6%) declined to answer. Every city, town, and unincorporated area in Alameda County has more registered Democrats than Republicans.[38]

On November 4, 2008 Alameda County voted 61.92% against Proposition 8, which won statewide, and which amended the California Constitution to ban same-sex marriage. The county garnered the sixth highest "no" vote, by percentage, of all California counties, and was the second largest county, by total voter turnout, to vote against it.[39]

Voter registration statistics

Cities by population and voter registration


The following table includes the number of incidents reported and the rate per 1,000 persons for each type of offense.

Cities by population and crime rates


The Alameda County Office of Education oversees seventeen K–12 school districts and one K–8 district in Alameda County. In all, there are approximately 10,000 teachers serving 225,000 students. The ACOE also services three community college districts with a total enrollment of approximately 55,000 students.

The Alameda County Library operates libraries in the cities of Albany, Dublin, Fremont, Newark and Union City and the unincorporated communities of Castro Valley and San Lorenzo. The cities of Alameda, Berkeley, Hayward, Livermore, Oakland, San Leandro, and Pleasanton have their own library systems.

Colleges and universities

Alameda County is home to the University of California, Berkeley, the flagship campus of the University of California system, and one of the largest and most prestigious research universities in the world.

Other colleges and universities located within Alameda county include:

School districts (K–12)


The Alameda County Arts Commission, a division of the county administration, under the California Arts Council, was created in 1965. Its fifteen appointed members act in an advisory capacity to the board of supervisors, in promoting the arts. The Oakland Museum of California has a substantial collection of California art works and historical artifacts.


The following sports teams play in Alameda County:

Club Sport Founded League Venue
California Golden Bears NCAA 1868 NCAA: Pac-12 California Memorial Stadium (Football), Haas Pavilion (Basketball), Evans Diamond (Baseball)
Oakland Athletics Baseball 1901 (in Oakland since 1968) Major League Baseball: American League Oakland–Alameda County Coliseum
Oakland Panthers Indoor football 2019 Indoor Football League Oakland Arena
Oakland Raiders American Football 1960 (in Los Angeles from 1982–1994) National Football League: American Conference. AFC West Oakland–Alameda County Coliseum
Golden State Warriors Basketball 1946 (In Oakland since 1971) National Basketball Association: Western Conference. Oracle Arena
East Bay FC Stompers Soccer 2012 (in San Francisco from 2012-2015) National Premier Soccer League: Golden Gate Conference Pioneer Stadium

Parks and recreation

There are more than 350 parks located within the county.[43] The East Bay Regional Park District operates within Alameda and neighboring Contra Costa County, with numerous parks within the county, including Tilden Regional Park, Redwood Regional Park, Anthony Chabot Regional Park, Coyote Hills Regional Park, Ardenwood Historic Farm, Pleasanton Ridge Regional Park and Vargas Plateau Regional Park. Eastshore State Park is located partially along the bay shore of northern Alameda County. The San Francisco Bay Trail, a project of the Association of Bay Area Governments, will run along the bay shore of the county.[44] The Hayward Area Recreation and Park District is the largest special park district in California.


Major highways

Mass transit

  • ACE train – commuter rail using existing railroad tracks; primarily brings commuters from San Joaquin County to Santa Clara County
  • AC Transit – local bus system in western Alameda County and west Contra Costa County, with additional service across the three bridges from Alameda County to downtown San Francisco, San Mateo, and Palo Alto
  • BART – commuter rail centered on northwest Oakland, primarily serving commuters to downtown San Francisco and downtown Oakland
  • Capitol Corridor – commuter rail using existing railroad tracks, extending from San Jose to Sacramento, running through western Alameda County
  • WHEELS – bus system in the cities of southeastern Alameda County
  • Union City Transit – local city bus service within Union City in addition to AC Transit
  • Emery-Go-Round – free bus service in Emeryville.
  • Alameda / Oakland Ferry and Harbor Bay Ferry – connect Oakland, Alameda, and Bay Farm Island with downtown San Francisco
  • San Joaquin – Amtrak route between Oakland and Bakersfield through Fresno and the Central Valley
  • VTA – commuter service between southern Alameda county and job centers in the Silicon Valley
  • Dumbarton Express – additional service across the Dumbarton Bridge between Fremont and Palo Alto


The main airport is the Oakland International Airport, with two general aviation airports, the Hayward Executive Airport and Livermore Municipal Airport.


The county operates hospitals and primary care clinics, through the Alameda County Medical Center. The Alameda County Community Food Bank nonprofit provides food bank resources to residents. The Family Emergency Shelter Coalition coordinates services for homeless families.


Alameda County has eight National Historic Landmarks: The Abbey, Joaquin Miller House, First Church of Christ, Scientist, USS Hornet (CVS-12) (aircraft carrier), Lake Merritt Wild Duck Refuge, Lightship WAL-605, Relief, Paramount Theatre, Potomac (Presidential yacht), and Room 307, Gilman Hall, University of California. The county has a large number of National Historic Places, as well as a number of California Historical Landmarks.

Sister county

Alameda has a sister county: Taoyuan County, Taiwan (now Taoyuan City).[45]



Census-designated places

Unincorporated communities

Former townships

  • Oakland Township – the northern portion subsequently became the cities of Berkeley and Albany.
  • Alameda Township – now essentially coterminous with the City of Alameda.
  • Brooklyn Township – mostly contained within Oakland and Piedmont.
  • Eden Township – partly incorporated into San Leandro and Hayward, the rest contains the communities of Castro Valley, San Lorenzo, and other unincorporated areas.
  • Washington Township – contains Union City, Newark, Fremont, and small unincorporated areas nearby.
  • Murray Township Contains cities of Dublin, Pleasanton, and Livermore, and substantial unincorporated areas including Sunol.

Population ranking

The population ranking of the following table is based on the 2010 census of Alameda County.[46]

county seat

Rank City/Town/etc. Municipal type Population (2010 Census)

1 Oakland City 390,724
2 Fremont City 214,089
3 Hayward City 144,186
4 Berkeley City 112,580
5 San Leandro City 84,950
6 Livermore City 80,968
7 Alameda City 73,812
8 Pleasanton City 70,285
9 Union City City 69,516
10 Castro Valley CDP 61,388
11 Dublin City 46,036
12 Newark City 42,573
13 San Lorenzo CDP 23,452
14 Ashland CDP 21,925
15 Albany City 18,539
16 Cherryland CDP 14,728
17 Piedmont City 10,667
18 Emeryville City 10,080
19 Fairview CDP 10,003
20 Sunol CDP 913

See also


  1. Other = Some other race + Two or more races
  2. Native American = Native Hawaiian or other Pacific Islander + American Indian or Alaska Native
  3. Percentage of registered voters with respect to total population. Percentages of party members with respect to registered voters follow.
  4. Only larceny-theft cases involving property over $400 in value are reported as property crimes.


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