Census tract · Alameda County
Census Tract 4309, Alameda County, California
Census Tract 4309, GEOID 06001430900, in Alameda County, California, entirely within Castro Valley. 5,539 residents in the ACS 2020-2024 5-year estimates (±843); the 2020 Census counted 5,137.
Residents, 2020-2024
5,539
±843 (90% margin)
2020 Census count: 5,137
Median household income
$120,000
±$23,044 (90% margin)
Alameda County: $129,367
Median home value
$910,400
±$99,162 (90% margin)
Alameda County: $1,090,100
Median gross rent
$2,303
±$137 (90% margin)
Alameda County: $2,357
Where is Census Tract 4309?
Census Tract 4309 is one of 379 census tracts in Alameda County, California. It covers 0.42 square miles of land, 12,144 residents per square mile in 2020. Its GEOID, 06001430900, names it uniquely (how tract numbers and GEOIDs work).
| Place | Share of the tract |
|---|---|
| Castro Valley | 100% |
4 census tracts border Census Tract 4309: Tract 4306 ($193,606), Tract 4307 ($145,521), Tract 4308 ($106,016) and Tract 4310 ($103,750). The figure in brackets is each tract's median household income.
Whether a tract counts as low- or moderate-income for bank lending (the Community Reinvestment Act) is set by the FFIEC against its metro area's family income: look it up in the FFIEC census geocoder.
Source: 2024 Gazetteer and 2020 block assignment files, U.S. Census Bureau · Census reference files
How many people live in Census Tract 4309?
The 2020-2024 American Community Survey puts Census Tract 4309's population at 5,539 (±843) in 1,810 households; the 2020 Census counted 5,137 residents and 1,925 housing units.
| Measure | Tract 4309 | Castro Valley |
|---|---|---|
| Total population | 5,539 ±843 | 65,001 |
| Households | 1,810 ±179 | 22,021 |
| Average household size | 2.93 ±0.33 | 2.90 |
| Housing units | 1,865 ±176 | 22,957 |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026); 2020 Census P.L. 94-171 · Check it at data.census.gov
Who lives in Census Tract 4309?
The median resident of Census Tract 4309 is 36.7 years old; 23.0% are under 18 and 11.0% are 65 or older. The largest group is non-Hispanic white residents at 27.8%, then Hispanic or Latino residents (of any race) at 27.2%. 36.3% of residents were born outside the United States.
| Measure | Tract 4309 | Castro Valley |
|---|---|---|
| Median age | 36.7 ±2.8 | 42.9 |
| Under 18 years | 23.0% ±5.3 pts | 20.8% |
| 65 years and over | 11.0% ±3.1 pts | 18.8% |
| Hispanic or Latino (any race) | 27.2% ±9.1 pts | 19.8% |
| White alone, not Hispanic | 27.8% ±8.0 pts | 33.5% |
| Black or African American alone, not Hispanic | 20.9% ±11.3 pts | 8.7% |
| Asian alone, not Hispanic | 22.0% ±7.1 pts | 32.9% |
| American Indian and Alaska Native alone, not Hispanic | 0.0% ±0.8 pts | 0.1% |
| Native Hawaiian and Other Pacific Islander alone, not Hispanic | 0.3% ±0.5 pts | 0.3% |
| Two or more races, not Hispanic | 1.9% ±1.6 pts | 4.6% |
| Some other race alone, not Hispanic | 0.0% ±0.8 pts | 0.2% |
| Born outside the United States | 36.3% ±7.5 pts | 31.0% |
| Speak a language other than English at home (age 5+) | 48.5% ±11.0 pts | 42.2% |
| Civilian veterans (age 18+) | 3.7% ±2.6 pts | 3.9% |
| With a disability | 8.6% ±2.7 pts | 9.8% |
| No health insurance coverage | 5.9% ±3.2 pts | 3.3% |
| High school graduate or higher (age 25+) | 88.2% ±5.9 pts | 91.7% |
| Bachelor's degree or higher (age 25+) | 36.3% ±6.6 pts | 44.5% |
| Graduate or professional degree (age 25+) | 11.2% ±4.6 pts | 17.5% |
| Lived in the same house a year earlier | 86.5% ±8.8 pts | 92.1% |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profiles DP02, DP05) · Check it at data.census.gov
What do households in Census Tract 4309 earn?
Half of the 1,810 households in Census Tract 4309 earn less than $120,000 a year (±$23,044), against $129,367 across Alameda County: 203rd highest of the county's 372 tracts with a reliable estimate. 14.7% of residents live below the poverty line.
| Measure | Tract 4309 | Castro Valley |
|---|---|---|
| Median household income | $120,000 ±$23,044 | $142,779 |
| Mean household income | $127,868 ±$13,383 | $175,307 |
| Per capita income | $43,934 ±$5,949 | $60,688 |
| People below the poverty line | 14.7% ±8.8 pts | 6.7% |
| Children under 18 below the poverty line | 22.6% ±22.0 pts | 5.8% |
| Households receiving SNAP | 13.6% ±6.9 pts | 6.7% |
| Households with a computer | 98.5% ±1.6 pts | 97.4% |
| Households with a broadband subscription | 94.1% ±4.2 pts | 96.7% |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profile DP03) · Check it at data.census.gov
What does housing cost in Census Tract 4309?
Owners occupy 35.6% of Census Tract 4309's occupied homes and renters 64.4%. The median owner-occupied home is valued at $910,400 by its owner (±$99,162). The median renter pays $2,303 a month including utilities, and 39.8% of renters pay 35% or more of their income on rent.
| Measure | Tract 4309 | Castro Valley |
|---|---|---|
| Median home value (owner-occupied) | $910,400 ±$99,162 | $1,104,600 |
| Median gross rent | $2,303 ±$137 | $2,554 |
| Renters paying 35% or more of income on rent | 39.8% ±11.4 pts | 45.6% |
| Median monthly owner costs, with a mortgage | $3,358 ±$531 | $3,627 |
| Owner-occupied homes | 35.6% ±8.2 pts | 72.5% |
| Renter-occupied homes | 64.4% ±8.2 pts | 27.5% |
| Housing units | 1,865 ±176 | 22,957 |
| Single-family detached homes | 28.4% ±7.6 pts | 73.3% |
| Mobile homes | 3.5% ±4.3 pts | 1.5% |
| Built 2020 or later | 0.0% ±2.3 pts | 0.7% |
| Built 2010 to 2019 | 8.8% ±5.5 pts | 2.5% |
| Built 1939 or earlier | 3.8% ±2.4 pts | 3.1% |
| Households with no vehicle | 10.4% ±6.4 pts | 5.5% |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profile DP04) · Check it at data.census.gov
How do people in Census Tract 4309 get to work?
61.4% of Census Tract 4309's workers drive alone and 21.6% work from home. The average trip to work takes 32.3 minutes.
| Measure | Tract 4309 | Castro Valley |
|---|---|---|
| In the labor force (age 16+) | 64.3% ±6.9 pts | 64.1% |
| Unemployment rate | 0.7% ±0.8 pts | 3.8% |
| Drove alone to work | 61.4% ±9.4 pts | 62.5% |
| Carpooled | 7.3% ±4.7 pts | 7.7% |
| Public transportation | 4.9% ±3.6 pts | 5.2% |
| Walked | 3.0% ±2.7 pts | 1.4% |
| Worked from home | 21.6% ±6.7 pts | 21.3% |
| Mean travel time to work | 32.3 min ±6.0 | 32.7 min |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profile DP03) · Check it at data.census.gov
How does Census Tract 4309 compare with the other tracts in Alameda County?
Among Alameda County's tracts with a reliable estimate, Census Tract 4309 ranks as shown below (1 = highest).
| Measure | In Alameda County | In Castro Valley |
|---|---|---|
| Population | 91st of 375 | 8th of 14 |
| Residents per square mile | 142nd of 378 | 1st of 14 |
| Median household income | 203rd of 372 | 10th of 14 |
| Per capita income | 288th of 377 | 14th of 14 |
| Median home value | 222nd of 366 | 10th of 14 |
| Median gross rent | 218th of 368 | 14th of 14 |
| Poverty rate | 72nd of 263 | 1st of 8 |
| Bachelor's degree or higher | 278th of 376 | 10th of 14 |
| Median age | 272nd of 377 | 13th of 14 |
| Owner-occupied share | 279th of 366 | 12th of 14 |
The tracts next to it on Alameda County's income ladder
| Tract | Rank | Median household income |
|---|---|---|
| Tract 4419.29 | 200th | $121,434±$60,794 · within the margin of this tract |
| Tract 4282 | 201st | $120,875±$43,824 · within the margin of this tract |
| Tract 4514.01 | 202nd | $120,610±$36,313 · within the margin of this tract |
| Tract 4309 | 203rd | $120,000±$23,044 |
| Tract 4515.06 | 204th | $119,757±$43,805 · within the margin of this tract |
| Tract 4423.02 | 205th | $119,745±$51,366 · within the margin of this tract |
| Tract 4403.04 | 206th | $119,732±$36,395 · within the margin of this tract |
"Within the margin": the two incomes differ by less than their combined 90% margins, so the survey cannot say which is higher and the ranks between them are not firm.
Source: PlainCities ranks computed from the American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) · How ranks are computed
How reliable are the figures for Census Tract 4309?
Every figure for Census Tract 4309 on this page has a coefficient of variation under 40%, the Census Bureau's threshold for a usable estimate.
A census tract's figures rest on a few hundred sampled households over five years, so its margins are wider than a city's. Two tracts differ only when the gap between them is larger than their combined 90% margin (the square root of the sum of the two squared margins). How to read a margin of error.
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026): margins of error as published · Check it at data.census.gov
How these figures are made: methodology and release checks · reading a margin of error · every state · corrections