Census tract · Ada County
Census Tract 21, Ada County, Idaho
Census Tract 21, GEOID 16001002100, in Ada County, Idaho, mostly within Boise City (73% of its census blocks). 2,164 residents in the ACS 2020-2024 5-year estimates (±275); the 2020 Census counted 2,070.
Residents, 2020-2024
2,164
±275 (90% margin)
2020 Census count: 2,070
Median household income
$102,308
±$10,105 (90% margin)
Ada County: $91,502
Median home value
$474,500
±$28,095 (90% margin)
Ada County: $512,300
Median gross rent
$1,580
±$291 (90% margin)
Ada County: $1,577
Where is Census Tract 21?
Census Tract 21 is one of 129 census tracts in Ada County, Idaho. It covers 17.86 square miles of land, 116 residents per square mile in 2020. Its GEOID, 16001002100, names it uniquely (how tract numbers and GEOIDs work).
| Place | Share of the tract |
|---|---|
| Boise City | 73% |
13 census tracts border Census Tract 21: Tract 8.03 ($115,958), Tract 8.10 ($91,553), Tract 16 ($69,737), Tract 18 ($70,513), Tract 19 ($74,819), Tract 22.28 ($91,915), Tract 22.29 ($108,601), Tract 22.31 ($88,438), Tract 104.11 ($107,583), Tract 105.01 ($119,554), Tract 105.03 ($107,283), Tract 105.05 ($103,293) and Tract 105.06 ($133,125). 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 21?
The 2020-2024 American Community Survey puts Census Tract 21's population at 2,164 (±275) in 902 households; the 2020 Census counted 2,070 residents and 858 housing units.
| Measure | Tract 21 | Boise City |
|---|---|---|
| Total population | 2,164±275 | 237,242 |
| Households | 902±122 | 101,178 |
| Average household size | 2.38±0.16 | 2.28 |
| Housing units | 909±119 | 106,279 |
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 21?
The median resident of Census Tract 21 is 52.1 years old; 16.4% are under 18 and 26.0% are 65 or older. The largest group is non-Hispanic white residents at 81.9%, then non-Hispanic Black residents at 8.3%. 11.9% of residents were born outside the United States.
| Measure | Tract 21 | Boise City |
|---|---|---|
| Median age | 52.1±6.0 | 38.6 |
| Under 18 years | 16.4%±2.9 pts | 18.5% |
| 65 years and over | 26.0%±4.0 pts | 16.2% |
| Hispanic or Latino (any race) | 5.9%±3.3 pts | 9.6% |
| White alone, not Hispanic | 81.9%±7.4 pts | 79.5% |
| Black or African American alone, not Hispanic | 8.3%±6.2 pts | 1.6% |
| Asian alone, not Hispanic | 2.6%±2.1 pts | 3.7% |
| American Indian and Alaska Native alone, not Hispanic | 0.0%±1.6 pts | 0.3% |
| Native Hawaiian and Other Pacific Islander alone, not Hispanic | 0.0%±1.6 pts | 0.3% |
| Two or more races, not Hispanic | 1.2%±1.4 pts | 4.7% |
| Some other race alone, not Hispanic | 0.1%±0.2 pts | 0.4% |
| Born outside the United States | 11.9%±6.2 pts | 7.9% |
| Speak a language other than English at home (age 5+) | 14.3%±7.5 pts | 11.1% |
| Civilian veterans (age 18+) | 14.6%±3.7 pts | 7.1% |
| With a disability | 14.8%±5.2 pts | 13.2% |
| No health insurance coverage | 5.8%±3.1 pts | 7.1% |
| High school graduate or higher (age 25+) | 95.1%±3.3 pts | 94.9% |
| Bachelor's degree or higher (age 25+) | 38.6%±7.5 pts | 47.5% |
| Graduate or professional degree (age 25+) | 13.4%±5.2 pts | 17.7% |
| Lived in the same house a year earlier | 94.8%±3.6 pts | 81.9% |
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 21 earn?
Half of the 902 households in Census Tract 21 earn less than $102,308 a year (±$10,105), against $91,502 across Ada County: 48th highest of the county's 128 tracts with a reliable estimate. 9.1% of residents live below the poverty line.
| Measure | Tract 21 | Boise City |
|---|---|---|
| Median household income | $102,308±$10,105 | $83,904 |
| Mean household income | $114,454±$11,902 | $114,774 |
| Per capita income | $48,131±$5,355 | $49,861 |
| People below the poverty line | 9.1%±4.6 pts | 10.6% |
| Children under 18 below the poverty line | 2.2%±3.0 pts | 11.1% |
| Households receiving SNAP | 5.7%±3.4 pts | 6.4% |
| Households with a computer | 95.6%±4.3 pts | 97.6% |
| Households with a broadband subscription | 91.8%±5.7 pts | 93.7% |
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 21?
Owners occupy 91.0% of Census Tract 21's occupied homes and renters 9.0%. The median owner-occupied home is valued at $474,500 by its owner (±$28,095). The median renter pays $1,580 a month including utilities.
| Measure | Tract 21 | Boise City |
|---|---|---|
| Median home value (owner-occupied) | $474,500±$28,095 | $484,800 |
| Median gross rent | $1,580±$291 | $1,446 |
| Renters paying 35% or more of income on rent | 19.6%±21.0 pts | 38.4% |
| Median monthly owner costs, with a mortgage | $1,806±$181 | $1,779 |
| Owner-occupied homes | 91.0%±4.0 pts | 63.2% |
| Renter-occupied homes | 9.0%±4.0 pts | 36.8% |
| Housing units | 909±119 | 106,279 |
| Single-family detached homes | 90.4%±4.3 pts | 64.4% |
| Mobile homes | 3.0%±2.4 pts | 3.0% |
| Built 2020 or later | 1.4%±1.3 pts | 2.0% |
| Built 2010 to 2019 | 9.7%±3.5 pts | 11.0% |
| Built 1939 or earlier | 0.4%±0.7 pts | 6.3% |
| Households with no vehicle | 1.2%±1.6 pts | 5.0% |
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 21 get to work?
71.4% of Census Tract 21's workers drive alone and 17.2% work from home. The average trip to work takes 23.7 minutes.
| Measure | Tract 21 | Boise City |
|---|---|---|
| In the labor force (age 16+) | 62.1%±5.5 pts | 67.4% |
| Unemployment rate | 1.6%±1.5 pts | 3.6% |
| Drove alone to work | 71.4%±7.2 pts | 67.6% |
| Carpooled | 7.2%±4.5 pts | 7.5% |
| Public transportation | 0.0%±3.1 pts | 0.5% |
| Walked | 2.7%±2.9 pts | 2.9% |
| Worked from home | 17.2%±6.3 pts | 17.6% |
| Mean travel time to work | 23.7 min±4.7 | 18.9 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 21 compare with the other tracts in Ada County?
Among Ada County's tracts with a reliable estimate, Census Tract 21 ranks as shown below (1 = highest).
| Measure | In Ada County | In Boise City |
|---|---|---|
| Population | 122nd of 129 | 62nd of 67 |
| Residents per square mile | 125th of 129 | 65th of 67 |
| Median household income | 48th of 128 | 19th of 66 |
| Per capita income | 60th of 129 | 28th of 67 |
| Median home value | 76th of 127 | 33rd of 65 |
| Median gross rent | 75th of 119 | 30th of 64 |
| Poverty rate | 38th of 68 | 26th of 47 |
| Bachelor's degree or higher | 86th of 129 | 49th of 67 |
| Median age | 6th of 129 | 2nd of 67 |
| Owner-occupied share | 18th of 127 | 4th of 65 |
The tracts next to it on Ada County's income ladder
| Tract | Rank | Median household income |
|---|---|---|
| Tract 103.61 | 45th | $106,273±$12,480 · within the margin of this tract |
| Tract 103.63 | 46th | $104,079±$21,758 · within the margin of this tract |
| Tract 105.05 | 47th | $103,293±$12,326 · within the margin of this tract |
| Tract 21 | 48th | $102,308±$10,105 |
| Tract 104.07 | 49th | $102,220±$20,446 · within the margin of this tract |
| Tract 103.43 | 50th | $101,151±$34,916 · within the margin of this tract |
| Tract 103.40 | 51st | $99,750±$44,275 · 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 21?
2 of the 18 figures for Census Tract 21 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