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Alameda County, California facts for kids

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Alameda County
Lake Merritt Oakland California panorama.jpg
CampanileMtTamalpiasSunset-original.jpg
Hayward water tower, California.jpg
Lake Elizabeth in Fremont Central Park.JPG
MCB-pleasanton-ca.jpg
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
Flag of Alameda County
Flag
Official seal of Alameda County
Seal
Location in the state of California
Location in the state of California
Country United States
State California
Region San Francisco Bay Area
Incorporated March 25, 1853
Named for Rancho Arroyo de la Alameda (also see Alameda Creek)
County seat Oakland
Largest city Oakland (population)
Fremont (area)
Government
 • Type Council–CAO
 • Body Alameda County Board of Supervisors
Area
 • Total 821 sq mi (2,130 km2)
 • Land 739 sq mi (1,910 km2)
 • Water 82 sq mi (210 km2)
Highest elevation
3,843 ft (1,171 m)
Population
 (2020)
 • Total 1,682,353
 • Estimate 
(2023)
1,622,188 Decrease
 • Density 2,049.2/sq mi (791.2/km2)
GDP
 • Total $168.506 billion (2022)
Time zone UTC-8 (Pacific Time Zone)
 • Summer (DST) UTC-7 (Pacific Daylight Time)
Area codes 510, 341, 925
FIPS code 06-001
Congressional districts 10th, 12th, 14th, 17th

Alameda County (say it: AL-ə-MEE-də) is a county in the state of California. It's located in the San Francisco Bay Area, mostly in the East Bay region. In 2020, about 1.68 million people lived here, making it the 7th most populated county in California. The main city and county seat is Oakland.

The name Alameda comes from a Spanish word. It means "a grove of poplars" or "a street lined with trees." Early Spanish explorers saw willow and sycamore trees along a creek here. They called it Arroyo de la Alameda. Today, that creek is known as Alameda Creek.

History of Alameda County

Alameda County was created on March 25, 1853. It was formed from parts of Contra Costa County and Santa Clara County.

When the county first started, its main office (county seat) was in Alvarado. This area is now part of Union City. In 1856, the county seat moved to San Leandro. But in 1868, an earthquake on the Hayward Fault destroyed the courthouse there.

From 1872 to 1875, the county seat was in Brooklyn. Brooklyn is now part of Oakland. Since 1873, Oakland has been the permanent county seat.

In the late 1800s and early 1900s, many areas here grew as "trolley car suburbs." People could live here and easily travel to San Francisco by trolley and ferry. Over time, this region changed from Native American lands and ranches to busy cities and suburbs.

Geography and Climate

Oaklandatnight02192006
View of downtown Oakland looking west across Lake Merritt
BerkeleyAndBayAtNight
View of Berkeley and the San Francisco Bay at nightfall
Mission-SJ
The reconstructed mission at Mission San José (located in Fremont)

Alameda County covers about 821 square miles. About 739 square miles are land, and 82 square miles (10%) are water. The San Francisco Bay is on the western side of the county.

The Berkeley Hills form part of the county's northeastern border. A flat area, called a coastal plain, runs along the bay. This is where most people in Oakland live. The Livermore Valley is in the eastern part of the county. The Amador Valley is next to it, stretching west to the Pleasanton Ridge. The Diablo Range has the county's highest mountains. This area is not very populated.

The Hayward Fault is a major earthquake fault line. It runs through the most populated parts of Alameda County. Another fault, the Calaveras Fault, is in the southeastern part of the county.

Areas near the Bay have a mild, wet winter and dry, warm summer climate. This is called a warm-summer Mediterranean climate. Areas further inland, like Livermore, have much hotter summers.

Climate data for Oakland Museum (1981–2010 normals, extremes 1970–present)
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
Record high °F (°C) 78
(26)
82
(28)
88
(31)
97
(36)
105
(41)
106
(41)
103
(39)
99
(37)
109
(43)
103
(39)
84
(29)
75
(24)
109
(43)
Mean maximum °F (°C) 67.0
(19.4)
72.4
(22.4)
75.9
(24.4)
82.8
(28.2)
85.5
(29.7)
89.1
(31.7)
87.3
(30.7)
88.7
(31.5)
89.7
(32.1)
87.8
(31.0)
75.8
(24.3)
66.5
(19.2)
94.7
(34.8)
Mean daily maximum °F (°C) 58.0
(14.4)
61.8
(16.6)
63.6
(17.6)
66.0
(18.9)
68.8
(20.4)
71.2
(21.8)
71.7
(22.1)
73.0
(22.8)
74.1
(23.4)
71.7
(22.1)
64.6
(18.1)
58.1
(14.5)
66.6
(19.2)
Daily mean °F (°C) 51.4
(10.8)
54.7
(12.6)
56.4
(13.6)
58.3
(14.6)
61.1
(16.2)
63.5
(17.5)
64.3
(17.9)
65.6
(18.7)
66.0
(18.9)
63.3
(17.4)
57.1
(13.9)
51.8
(11.0)
59.2
(15.1)
Mean daily minimum °F (°C) 44.7
(7.1)
47.7
(8.7)
49.1
(9.5)
50.5
(10.3)
53.5
(11.9)
55.7
(13.2)
56.9
(13.8)
58.1
(14.5)
57.8
(14.3)
55.1
(12.8)
49.8
(9.9)
45.4
(7.4)
51.9
(11.1)
Mean minimum °F (°C) 38.0
(3.3)
40.0
(4.4)
42.2
(5.7)
45.2
(7.3)
49.1
(9.5)
51.9
(11.1)
54.0
(12.2)
55.5
(13.1)
53.8
(12.1)
49.0
(9.4)
41.6
(5.3)
37.3
(2.9)
36.0
(2.2)
Record low °F (°C) 30
(−1)
29
(−2)
34
(1)
37
(3)
43
(6)
48
(9)
51
(11)
50
(10)
48
(9)
43
(6)
36
(2)
26
(−3)
26
(−3)
Average precipitation inches (mm) 4.59
(117)
4.65
(118)
3.52
(89)
1.32
(34)
0.73
(19)
0.12
(3.0)
0.00
(0.00)
0.07
(1.8)
0.23
(5.8)
1.29
(33)
3.07
(78)
4.44
(113)
24.09
(612)
Average precipitation days (≥ 0.01 in.) 10.2 10.5 10.7 5.9 3.4 1.0 0.1 0.4 1.2 3.5 8.1 10.4 69.1
Source: NOAA
Climate data for Livermore, California (1903–2013)
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
Record high °F (°C) 77
(25)
80
(27)
88
(31)
96
(36)
108
(42)
113
(45)
113
(45)
112
(44)
115
(46)
106
(41)
93
(34)
79
(26)
113
(45)
Mean maximum °F (°C) 66.9
(19.4)
71.4
(21.9)
77.9
(25.5)
85.8
(29.9)
94.3
(34.6)
102.0
(38.9)
104.3
(40.2)
102.8
(39.3)
101.2
(38.4)
92.6
(33.7)
79.0
(26.1)
67.8
(19.9)
106.3
(41.3)
Mean daily maximum °F (°C) 56.8
(13.8)
61.2
(16.2)
65.2
(18.4)
70.5
(21.4)
76.4
(24.7)
83.1
(28.4)
89.0
(31.7)
88.2
(31.2)
86.0
(30.0)
77.7
(25.4)
66.3
(19.1)
57.5
(14.2)
73.2
(22.9)
Mean daily minimum °F (°C) 36.7
(2.6)
39.4
(4.1)
41.3
(5.2)
43.6
(6.4)
47.6
(8.7)
51.7
(10.9)
54.2
(12.3)
54.0
(12.2)
52.5
(11.4)
47.7
(8.7)
41.1
(5.1)
37.0
(2.8)
45.6
(7.6)
Mean minimum °F (°C) 26.4
(−3.1)
29.5
(−1.4)
32.1
(0.1)
34.9
(1.6)
39.3
(4.1)
44.4
(6.9)
47.7
(8.7)
47.8
(8.8)
44.5
(6.9)
38.3
(3.5)
30.5
(−0.8)
26.7
(−2.9)
24.5
(−4.2)
Record low °F (°C) 18
(−8)
21
(−6)
22
(−6)
29
(−2)
32
(0)
38
(3)
36
(2)
36
(2)
35
(2)
29
(−2)
22
(−6)
18
(−8)
18
(−8)
Average precipitation inches (mm) 2.97
(75)
2.47
(63)
2.15
(55)
1.00
(25)
.44
(11)
.11
(2.8)
.02
(0.51)
.04
(1.0)
.22
(5.6)
.67
(17)
1.54
(39)
2.56
(65)
14.19
(359.91)
Average precipitation days (≥ .01 in) 10 9 9 6 3 1 0 0 1 3 7 9 58
Average snowy days trace 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.1
Source: WRCC and pogodaiklimat.ru

Neighboring Counties

Alameda County shares borders with several other counties:

Protected Natural Areas

Part of the Don Edwards San Francisco Bay National Wildlife Refuge is located in Alameda County. This area helps protect wildlife and their homes.

People and Population

Historical population
Census Pop.
1860 8,927
1870 24,237 171.5%
1880 62,976 159.8%
1890 93,864 49.0%
1900 130,197 38.7%
1910 246,131 89.0%
1920 344,177 39.8%
1930 474,883 38.0%
1940 513,011 8.0%
1950 740,315 44.3%
1960 908,209 22.7%
1970 1,073,184 18.2%
1980 1,105,379 3.0%
1990 1,279,182 15.7%
2000 1,443,741 12.9%
2010 1,510,271 4.6%
2020 1,682,353 11.4%
2023 (est.) 1,622,188 7.4%
U.S. Decennial Census
1790–1960 1900–1990
1990–2000 2010 2020

Alameda County is known for being very diverse. This means people from many different backgrounds live here.

Population in 2020

In the 2020 census, Alameda County had 1,682,353 people. Here's a look at the different groups:

Alameda County, California – Racial and ethnic composition
Note: the US Census treats Hispanic/Latino as an ethnic category. This table excludes Latinos from the racial categories and assigns them to a separate category. Hispanics/Latinos may be of any race.
Race / Ethnicity (NH = Non-Hispanic) Pop 2000 Pop 2010 Pop 2020 % 2000 % 2010 % 2020
White alone (NH) 591,095 514,559 472,277 40.94% 34.07% 28.07%
Black or African American alone (NH) 211,124 184,126 159,499 14.62% 12.19% 9.48%
Native American or Alaska Native alone (NH) 5,306 4,189 4,131 0.37% 0.28% 0.25%
Asian alone (NH) 292,673 390,524 540,511 20.27% 25.86% 32.13%
Pacific Islander alone (NH) 8,458 11,931 13,209 0.59% 0.79% 0.79%
Other Race alone (NH) 4,676 4,191 10,440 0.32% 0.28% 0.62%
Mixed Race or Multi-Racial (NH) 56,499 60,862 88,537 3.91% 4.03% 5.26%
Hispanic or Latino (any race) 273,910 339,889 393,749 18.97% 22.51% 23.40%
Total 1,443,741 1,510,271 1,682,353 100.00% 100.00% 100.00%

In 2014, a study found Alameda County to be the fourth most racially diverse county in the United States. It was also the most diverse county in California. The 2020 census shows that Alameda County has one of the highest percentages of Asian residents. It is one of the only counties in the continental U.S. where Asian people make up the largest group. This group includes many people of Chinese, Indian, and Filipino backgrounds.

Population Breakdown (2019)

Ethnic Origins in Alameda County, CA
Ethnic origins in Alameda County

Here's a look at the different groups in Alameda County based on 2019 estimates:

  • White: 38.8% (this includes people who identify as both White and Hispanic)
  • Asian: 31.1%
  • Some Other Race: 11.5%
  • Black or African American: 10.7%
  • Two or more races: 6.4%
  • Native American and Alaskan Native: 0.8%
  • Pacific Islander: 0.8%


Circle frame-1.svg

Racial Makeup of Alameda County (2019)      White alone (38.84%)     Black alone (10.66%)     Native American alone (0.76%)     Asian Alone (31.13%)     Pacific Islander Alone (0.81%)     Other race alone (11.45%)     Two or more races (6.35%)


Circle frame-1.svg

Racial Makeup of Alameda County excluding Hispanics from racial categories (2019)
NH=Non-Hispanic      White alone (30.43%)     Black alone (10.33%)     Native American alone (0.33%)     Asian Alone (30.93%)     Pacific Islander Alone (0.77%)     Other race alone (0.47%)     Two or more races (4.41%)     Hispanic Any Race (22.32%)


Circle frame-1.svg

Racial Makeup of Hispanics in Alameda County (2019)      White alone (37.69%)     Black alone (1.48%)     Native American alone (1.91%)     Asian alone (0.89%)     Pacific Islander alone (0.17%)     Other race alone (49.16%)     Two or more races (8.69%)

Asian Americans are now the largest racial group in Alameda County. White Non-Hispanic Americans are the largest minority group. About 22.3% of the population is Hispanic-Latino. This group is the third largest minority group in the county. Most Hispanics in Alameda County are of Mexican descent.

Education in Alameda County

The Alameda County Office of Education helps oversee 17 school districts for students from kindergarten to 12th grade. They also help three community college districts. About 10,000 teachers work with 225,000 students in the county.

The Alameda County Library has libraries in several cities and communities. Some cities, like Oakland and Berkeley, have their own separate library systems.

Colleges and Universities

Alameda County is home to many colleges and universities. One of the most famous is the University of California, Berkeley. It's a very large and important research university.

Other colleges and universities include:

  • Berkeley City College
  • California State University, East Bay
  • Chabot College
  • College of Alameda
  • Graduate Theological Union
  • Laney College
  • Las Positas College
  • Merritt College
  • Mills College at Northeastern University
  • Ohlone College
  • Samuel Merritt University

Public School Districts

Here are some of the school districts in Alameda County:

  • Alameda Unified School District
  • Albany Unified School District
  • Berkeley Unified School District
  • Castro Valley Unified School District
  • Dublin Unified School District
  • Emery Unified School District
  • Fremont Unified School District
  • Hayward Unified School District
  • Livermore Valley Joint Unified School District
  • New Haven Unified School District
  • Newark Unified School District
  • Oakland Unified School District
  • Piedmont Unified School District
  • Pleasanton Unified School District
  • San Leandro Unified School District
  • San Lorenzo Unified School District
  • Sunol Glen Unified School District

Arts and Culture

The Alameda County Arts Commission works to support and promote the arts in the county. The Oakland Museum of California has a large collection of California art and historical items.

Sports Teams

Here are some sports teams that play in Alameda County:

Club Sport Founded League Venue
California Golden Bears NCAA 1868 NCAA: ACC California Memorial Stadium (Football), Haas Pavilion (Basketball), Evans Diamond (Baseball)
East Bay FC Stompers Soccer 2012 (in San Francisco from 2012 to 2015) National Premier Soccer League: Golden Gate Conference Pioneer Stadium
Oakland Roots Soccer 2018 USL Championship Pioneer Stadium

Fun Events

The county hosts an annual fair at the Alameda County Fairgrounds in Pleasanton. The fair takes place for four weekends from June to July. You can enjoy horse racing, carnival rides, 4-H exhibits, and live music.

Parks and Outdoor Fun

Alameda County has over 350 parks! The East Bay Regional Park District manages many of these parks. Some popular ones include Tilden Regional Park, Redwood Regional Park, and Coyote Hills Regional Park. The San Francisco Bay Trail is a path that will run along the bay shore in the county.

Getting Around (Transportation)

Main Roads

  • I-80 (CA).svg Interstate 80
  • I-205 (CA).svg Interstate 205
  • I-238 (CA).svg Interstate 238
  • I-580 (CA).svg Interstate 580
  • I-680 (CA).svg Interstate 680
  • I-880 (CA).svg Interstate 880
  • I-980 (CA).svg Interstate 980
  • California 13.svg State Route 13
  • California 24.svg State Route 24
  • California 61.svg State Route 61
  • California 77.svg State Route 77
  • California 84.svg State Route 84
  • California 92.svg State Route 92
  • California 123.svg State Route 123
  • California 185.svg State Route 185
  • California 238.svg State Route 238
  • California 262.svg State Route 262

Public Transportation

Trains

  • Altamont Corridor Express (ACE): A train for people commuting from San Joaquin County.
  • Amtrak: Long-distance trains like the California Zephyr and Coast Starlight stop here. The Capitol Corridor and San Joaquins also serve the county.
  • Bay Area Rapid Transit (BART): A subway and elevated train system that connects many cities in the Bay Area, including Oakland and San Francisco.
  • Valley Link: A planned train service for the future.

Buses

  • AC Transit: The main local bus system in western Alameda County. It also connects to San Francisco.
  • WHEELS: A bus system for cities in southeastern Alameda County.
  • Other local bus services include Union City Transit and Emery-Go-Round.

Ferries

  • Alameda / Oakland Ferry and Harbor Bay Ferry: These ferries connect Oakland, Alameda, and Bay Farm Island to downtown San Francisco by water.

Airports

The main airport in the county is the Oakland International Airport. There are also two smaller airports for general aviation: the Hayward Executive Airport and Livermore Municipal Airport.

Community Services

Alameda Health System runs the public health system in the county. They operate five hospitals and several clinics. The Alameda County Community Food Bank helps provide food for residents. The Family Emergency Shelter Coalition helps homeless families.

Important Landmarks

Alameda County has many important historical places. Eight of them are National Historic Landmarks. These include:

The county also has many other places listed on the National Register of Historic Places and California Historical Landmarks.

Sister County

Alameda County has a "sister county" relationship with Taoyuan City in Taiwan.

Cities and Communities

Cities and census designated places of Alameda County

Cities

No.
on Map
City Year
incorporated
Population,
2020
1 Alameda 1854 78,280
2 Albany 1908 20,271
3 Berkeley 1878 124,321
4 Dublin 1982 72,589
5 Emeryville 1896 12,905
6 Fremont 1956 230,504
7 Hayward 1876 162,954
8 Livermore 1876 87,955
9 Newark 1955 47,529
10 Oakland (county seat) 1852 440,646
11 Piedmont 1907 11,270
12 Pleasanton 1894 79,871
13 San Leandro 1872 91,008
14 Union City 1959 70,143

Census-Designated Places (CDPs)

These are areas that are like towns but are not officially incorporated as cities.

Unincorporated Communities

These are smaller communities that are not part of any city or CDP.

Population Ranking of Communities

This table shows the population of cities and CDPs in Alameda County, based on the 2020 census.

county seat

Rank City/Town/etc. Municipal type Population (2020 Census)
1 Oakland City 440,646
2 Fremont City 230,504
3 Hayward City 162,954
4 Berkeley City 124,321
5 San Leandro City 91,008
6 Livermore City 87,955
7 Pleasanton City 79,871
8 Alameda City 78,280
9 Dublin City 72,589
10 Union City City 70,143
11 Castro Valley CDP 66,441
12 Newark City 47,529
13 San Lorenzo CDP 29,581
14 Ashland CDP 23,823
15 Albany City 20,271
16 Cherryland CDP 15,808
17 Emeryville City 12,905
18 Fairview CDP 11,341
19 Piedmont City 11,270
20 Sunol CDP 922

Images for kids

See Also

Kids robot.svg In Spanish: Condado de Alameda para niños

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