Census tract · Boulder County
Census Tract 121.05, Boulder County, Colorado
Census Tract 121.05, GEOID 08013012105, in Boulder County, Colorado, mostly within Boulder (94% of its census blocks). 6,180 residents in the ACS 2020-2024 5-year estimates (±773); the 2020 Census counted 6,635.
Residents, 2020-2024
6,180
±773 (90% margin)
2020 Census count: 6,635
Median household income
$102,112
±$10,353 (90% margin)
Boulder County: $103,994
Median home value
$886,600
±$199,037 (90% margin)
Boulder County: $756,300
Median gross rent
$2,224
±$334 (90% margin)
Boulder County: $1,966
Where is Census Tract 121.05?
Census Tract 121.05 is one of 78 census tracts in Boulder County, Colorado. It covers 0.95 square miles of land, 6,955 residents per square mile in 2020. Its GEOID, 08013012105, names it uniquely (how tract numbers and GEOIDs work).
| Place | Share of the tract |
|---|---|
| Boulder | 94% |
6 census tracts border Census Tract 121.05: Tract 121.01 ($244,179), Tract 121.03 ($118,750), Tract 121.04 ($155,313), Tract 121.06 ($132,227), Tract 127.01 ($139,597) and Tract 137.04 ($86,163). 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 121.05?
The 2020-2024 American Community Survey puts Census Tract 121.05's population at 6,180 (±773) in 2,532 households; the 2020 Census counted 6,635 residents and 2,754 housing units.
| Measure | Tract 121.05 | Boulder |
|---|---|---|
| Total population | 6,180 ±773 | 106,433 |
| Households | 2,532 ±241 | 44,432 |
| Average household size | 2.43 ±0.19 | 2.12 |
| Housing units | 2,630 ±226 | 47,465 |
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 121.05?
The median resident of Census Tract 121.05 is 42.2 years old; 20.1% are under 18 and 9.3% are 65 or older. The largest group is non-Hispanic white residents at 60.1%, then Hispanic or Latino residents (of any race) at 24.3%. 21.4% of residents were born outside the United States.
| Measure | Tract 121.05 | Boulder |
|---|---|---|
| Median age | 42.2 ±3.2 | 28.8 |
| Under 18 years | 20.1% ±4.6 pts | 11.8% |
| 65 years and over | 9.3% ±2.3 pts | 12.7% |
| Hispanic or Latino (any race) | 24.3% ±7.7 pts | 10.7% |
| White alone, not Hispanic | 60.1% ±7.0 pts | 78.0% |
| Black or African American alone, not Hispanic | 0.1% ±0.1 pts | 1.0% |
| Asian alone, not Hispanic | 5.2% ±3.9 pts | 5.4% |
| American Indian and Alaska Native alone, not Hispanic | 0.0% ±0.7 pts | 0.2% |
| Native Hawaiian and Other Pacific Islander alone, not Hispanic | 0.0% ±0.7 pts | 0.0% |
| Two or more races, not Hispanic | 9.3% ±5.2 pts | 4.4% |
| Some other race alone, not Hispanic | 1.1% ±1.6 pts | 0.3% |
| Born outside the United States | 21.4% ±5.7 pts | 10.8% |
| Speak a language other than English at home (age 5+) | 28.0% ±8.3 pts | 14.9% |
| Civilian veterans (age 18+) | 3.1% ±2.4 pts | 2.7% |
| With a disability | 7.2% ±2.9 pts | 7.6% |
| No health insurance coverage | 10.7% ±5.1 pts | 3.4% |
| High school graduate or higher (age 25+) | 87.4% ±6.2 pts | 97.3% |
| Bachelor's degree or higher (age 25+) | 70.9% ±7.8 pts | 76.8% |
| Graduate or professional degree (age 25+) | 42.7% ±7.5 pts | 40.4% |
| Lived in the same house a year earlier | 85.3% ±6.3 pts | 65.9% |
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 121.05 earn?
Half of the 2,532 households in Census Tract 121.05 earn less than $102,112 a year (±$10,353), against $103,994 across Boulder County: 42nd highest of the county's 76 tracts with a reliable estimate. 13.4% of residents live below the poverty line.
| Measure | Tract 121.05 | Boulder |
|---|---|---|
| Median household income | $102,112 ±$10,353 | $87,493 |
| Mean household income | $146,850 ±$19,230 | $148,050 |
| Per capita income | $62,061 ±$9,251 | $63,074 |
| People below the poverty line | 13.4% ±5.8 pts | 21.5% |
| Children under 18 below the poverty line | 15.5% ±17.1 pts | 9.1% |
| Households receiving SNAP | 5.8% ±3.8 pts | 5.5% |
| Households with a computer | 98.3% ±1.7 pts | 99.0% |
| Households with a broadband subscription | 92.1% ±3.1 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 121.05?
Owners occupy 74.9% of Census Tract 121.05's occupied homes and renters 25.1%. The median owner-occupied home is valued at $886,600 by its owner (±$199,037). The median renter pays $2,224 a month including utilities, and 49.7% of renters pay 35% or more of their income on rent.
| Measure | Tract 121.05 | Boulder |
|---|---|---|
| Median home value (owner-occupied) | $886,600 ±$199,037 | $1,039,500 |
| Median gross rent | $2,224 ±$334 | $2,018 |
| Renters paying 35% or more of income on rent | 49.7% ±16.0 pts | 58.4% |
| Median monthly owner costs, with a mortgage | $3,438 ±$900 | $3,210 |
| Owner-occupied homes | 74.9% ±7.0 pts | 47.2% |
| Renter-occupied homes | 25.1% ±7.0 pts | 52.8% |
| Housing units | 2,630 ±226 | 47,465 |
| Single-family detached homes | 40.0% ±7.5 pts | 38.7% |
| Mobile homes | 17.5% ±5.6 pts | 2.0% |
| Built 2020 or later | 0.7% ±1.2 pts | 1.4% |
| Built 2010 to 2019 | 6.8% ±3.0 pts | 8.1% |
| Built 1939 or earlier | 0.0% ±1.6 pts | 7.5% |
| Households with no vehicle | 3.7% ±2.8 pts | 9.1% |
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 121.05 get to work?
46.5% of Census Tract 121.05's workers drive alone and 35.0% work from home. The average trip to work takes 16.6 minutes.
| Measure | Tract 121.05 | Boulder |
|---|---|---|
| In the labor force (age 16+) | 76.2% ±5.1 pts | 63.7% |
| Unemployment rate | 4.8% ±3.5 pts | 6.0% |
| Drove alone to work | 46.5% ±9.8 pts | 39.1% |
| Carpooled | 0.4% ±0.6 pts | 3.2% |
| Public transportation | 11.8% ±8.9 pts | 5.1% |
| Walked | 1.3% ±1.4 pts | 9.5% |
| Worked from home | 35.0% ±7.2 pts | 34.4% |
| Mean travel time to work | 16.6 min ±1.9 | 18.1 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 121.05 compare with the other tracts in Boulder County?
Among Boulder County's tracts with a reliable estimate, Census Tract 121.05 ranks as shown below (1 = highest).
| Measure | In Boulder County | In Boulder |
|---|---|---|
| Population | 10th of 78 | 3rd of 30 |
| Residents per square mile | 12th of 78 | 10th of 30 |
| Median household income | 42nd of 76 | 13th of 29 |
| Per capita income | 43rd of 78 | 16th of 30 |
| Median home value | 30th of 75 | 18th of 29 |
| Median gross rent | 23rd of 76 | 9th of 29 |
| Poverty rate | 21st of 57 | 16th of 26 |
| Bachelor's degree or higher | 35th of 78 | 21st of 30 |
| Median age | 34th of 78 | 8th of 30 |
| Owner-occupied share | 32nd of 76 | 7th of 28 |
The tracts next to it on Boulder County's income ladder
| Tract | Rank | Median household income |
|---|---|---|
| Tract 132.01 | 39th | $102,961±$22,581 · within the margin of this tract |
| Tract 133.05 | 40th | $102,262±$18,978 · within the margin of this tract |
| Tract 132.12 | 41st | $102,132±$9,445 · within the margin of this tract |
| Tract 121.05 | 42nd | $102,112±$10,353 |
| Tract 121.07 | 43rd | $99,948±$20,088 · within the margin of this tract |
| Tract 135.06 | 44th | $98,719±$11,277 · within the margin of this tract |
| Tract 125.08 | 45th | $97,019±$13,755 · 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 121.05?
2 of the 18 figures for Census Tract 121.05 on this page carry a coefficient of variation over 40% and are 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