Census tract · Contra Costa County
Census Tract 3551.12, Contra Costa County, California
Census Tract 3551.12, GEOID 06013355112, in Contra Costa County, California, partly within Blackhawk and Diablo. 5,544 residents in the ACS 2020-2024 5-year estimates (±764); the 2020 Census counted 5,636.
Residents, 2020-2024
5,544
±764 (90% margin)
2020 Census count: 5,636
Median household income
$206,932
±$61,295 (90% margin)
Contra Costa County: $127,229
Median home value
$2,000,000 or more
The survey's top or bottom value; no margin is published
Contra Costa County: $866,800
Median gross rent
$3,500 or more
The survey's top or bottom value; no margin is published
Contra Costa County: $2,375
Where is Census Tract 3551.12?
Census Tract 3551.12 is one of 242 census tracts in Contra Costa County, California. It covers 98.05 square miles of land, 57 residents per square mile in 2020. Its GEOID, 06013355112, names it uniquely (how tract numbers and GEOIDs work).
12 census tracts border Census Tract 3551.12: Tract 4507.52 in Alameda County ($250,000 or more), Tract 4511.04 in Alameda County ($183,846), Tract 4512.02 in Alameda County ($178,984), Tract 3040.01 ($156,941), Tract 3040.02 ($76,526), Tract 3462.04 ($250,000 or more), Tract 3462.05 ($233,333), Tract 3551.07 ($151,845), Tract 3551.13 ($250,000 or more), Tract 3551.23 ($250,000 or more), Tract 3551.26 ($250,000 or more) and Tract 3553.06 ($162,019). 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 3551.12?
The 2020-2024 American Community Survey puts Census Tract 3551.12's population at 5,544 (±764) in 2,141 households; the 2020 Census counted 5,636 residents and 2,170 housing units.
| Measure | Tract 3551.12 | Contra Costa County |
|---|---|---|
| Total population | 5,544 ±764 | 1,165,012 |
| Households | 2,141 ±259 | 414,417 |
| Average household size | 2.45 ±0.24 | 2.78 |
| Housing units | 2,230 ±244 | 429,260 |
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 3551.12?
The median resident of Census Tract 3551.12 is 51.9 years old; 15.6% are under 18 and 28.3% are 65 or older. The largest group is non-Hispanic white residents at 65.5%, then non-Hispanic Asian residents at 15.9%. 22.4% of residents were born outside the United States.
| Measure | Tract 3551.12 | Contra Costa County |
|---|---|---|
| Median age | 51.9 ±5.0 | 40.5 |
| Under 18 years | 15.6% ±3.4 pts | 22.0% |
| 65 years and over | 28.3% ±5.1 pts | 17.1% |
| Hispanic or Latino (any race) | 11.0% ±4.8 pts | 27.6% |
| White alone, not Hispanic | 65.5% ±6.6 pts | 38.1% |
| Black or African American alone, not Hispanic | 2.3% ±4.9 pts | 7.9% |
| Asian alone, not Hispanic | 15.9% ±3.9 pts | 18.6% |
| American Indian and Alaska Native alone, not Hispanic | 0.0% ±0.1 pts | 0.2% |
| Native Hawaiian and Other Pacific Islander alone, not Hispanic | 0.0% ±0.8 pts | 0.5% |
| Two or more races, not Hispanic | 4.7% ±3.5 pts | 6.3% |
| Some other race alone, not Hispanic | 0.6% ±0.8 pts | 0.8% |
| Born outside the United States | 22.4% ±5.6 pts | 26.6% |
| Speak a language other than English at home (age 5+) | 26.6% ±8.6 pts | 37.5% |
| Civilian veterans (age 18+) | 6.9% ±3.9 pts | 4.2% |
| With a disability | 6.1% ±2.7 pts | 11.1% |
| No health insurance coverage | 1.1% ±1.2 pts | 4.6% |
| High school graduate or higher (age 25+) | 98.3% ±1.3 pts | 89.6% |
| Bachelor's degree or higher (age 25+) | 65.2% ±5.8 pts | 45.2% |
| Graduate or professional degree (age 25+) | 25.9% ±6.6 pts | 17.7% |
| Lived in the same house a year earlier | 87.7% ±7.1 pts | 90.0% |
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 3551.12 earn?
Half of the 2,141 households in Census Tract 3551.12 earn less than $206,932 a year (±$61,295), against $127,229 across Contra Costa County: 35th highest of the county's 239 tracts with a reliable estimate. 5.7% of residents live below the poverty line.
| Measure | Tract 3551.12 | Contra Costa County |
|---|---|---|
| Median household income | $206,932 ±$61,295 | $127,229 |
| Mean household income | $374,009 ±$93,265 | $174,872 |
| Per capita income | $147,752 ±$35,800 | $62,927 |
| People below the poverty line | 5.7% ±3.1 pts | 8.4% |
| Children under 18 below the poverty line | 0.0% ±4.8 pts | 10.0% |
| Households receiving SNAP | 0.7% ±1.0 pts | 8.5% |
| Households with a computer | 99.3% ±0.9 pts | 97.7% |
| Households with a broadband subscription | 98.0% ±2.1 pts | 95.6% |
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 3551.12?
Owners occupy 90.7% of Census Tract 3551.12's occupied homes and renters 9.3%. The median owner-occupied home is valued at $2,000,000 or more by its owner (). The median renter pays $3,500 or more a month including utilities.
| Measure | Tract 3551.12 | Contra Costa County |
|---|---|---|
| Median home value (owner-occupied) | $2,000,000 or more | $866,800 |
| Median gross rent | $3,500 or more | $2,375 |
| Renters paying 35% or more of income on rent | 0.0% ±19.0 pts | 47.4% |
| Median monthly owner costs, with a mortgage | $4,000 or more | $3,435 |
| Owner-occupied homes | 90.7% ±5.4 pts | 68.0% |
| Renter-occupied homes | 9.3% ±5.4 pts | 32.0% |
| Housing units | 2,230 ±244 | 429,260 |
| Single-family detached homes | 96.0% ±3.6 pts | 67.5% |
| Mobile homes | 0.0% ±1.9 pts | 1.4% |
| Built 2020 or later | 0.0% ±1.9 pts | 1.1% |
| Built 2010 to 2019 | 0.5% ±0.8 pts | 5.8% |
| Built 1939 or earlier | 2.8% ±3.6 pts | 4.2% |
| Households with no vehicle | 0.3% ±0.6 pts | 5.2% |
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 3551.12 get to work?
44.8% of Census Tract 3551.12's workers drive alone and 35.7% work from home. The average trip to work takes 34.9 minutes.
| Measure | Tract 3551.12 | Contra Costa County |
|---|---|---|
| In the labor force (age 16+) | 51.5% ±7.8 pts | 64.7% |
| Unemployment rate | 2.8% ±3.1 pts | 6.5% |
| Drove alone to work | 44.8% ±10.6 pts | 59.7% |
| Carpooled | 4.7% ±5.7 pts | 10.0% |
| Public transportation | 3.4% ±3.8 pts | 5.4% |
| Walked | 10.9% ±7.8 pts | 1.8% |
| Worked from home | 35.7% ±8.7 pts | 21.3% |
| Mean travel time to work | 34.9 min ±8.8 | 35.3 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 3551.12 compare with the other tracts in Contra Costa County?
Among Contra Costa County's tracts with a reliable estimate, Census Tract 3551.12 ranks as shown below (1 = highest).
| Measure | In Contra Costa County |
|---|---|
| Population | 79th of 241 |
| Residents per square mile | 240th of 241 |
| Median household income | 35th of 239 |
| Per capita income | 4th of 241 |
| Median home value | 1st of 236 |
| Median gross rent | 1st of 236 |
| Poverty rate | 104th of 134 |
| Bachelor's degree or higher | 68th of 239 |
| Median age | 10th of 241 |
| Owner-occupied share | 31st of 240 |
The tracts next to it on Contra Costa County's income ladder
| Tract | Rank | Median household income |
|---|---|---|
| Tract 3451.03 | 32nd | $211,518±$37,270 · within the margin of this tract |
| Tract 3451.17 | 33rd | $209,013±$39,176 · within the margin of this tract |
| Tract 3383.02 | 34th | $207,105±$48,972 · within the margin of this tract |
| Tract 3551.12 | 35th | $206,932±$61,295 |
| Tract 3451.14 | 36th | $204,924±$29,935 · within the margin of this tract |
| Tract 3462.03 | 37th | $203,750±$46,135 · within the margin of this tract |
| Tract 3452.03 | 38th | $203,304±$57,040 · 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 3551.12?
1 of the 18 figures for Census Tract 3551.12 on this page carries a coefficient of variation over 40% and is marked with a ring: they come from a small sample, so read them as rough.
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