Census tract · Charleston County
Census Tract 21.05, Charleston County, South Carolina
Census Tract 21.05, GEOID 45019002105, in Charleston County, South Carolina, mostly within Seabrook Island (68% of its census blocks). 2,308 residents in the ACS 2020-2024 5-year estimates (±290); the 2020 Census counted 2,184.
Residents, 2020-2024
2,308
±290 (90% margin)
2020 Census count: 2,184
Median household income
$132,188
±$32,027 (90% margin)
Charleston County: $88,494
Median home value
$1,029,400
±$86,565 (90% margin)
Charleston County: $489,100
Median gross rent
$3,500 or more
The survey's top or bottom value; no margin is published
Charleston County: $1,620
Where is Census Tract 21.05?
Census Tract 21.05 is one of 99 census tracts in Charleston County, South Carolina. It covers 8.17 square miles of land, 267 residents per square mile in 2020. Its GEOID, 45019002105, names it uniquely (how tract numbers and GEOIDs work).
| Place | Share of the tract |
|---|---|
| Seabrook Island | 68% |
| Kiawah Island | 15% |
4 census tracts border Census Tract 21.05: Tract 21.03 ($109,103), Tract 21.04 ($213,594), Tract 22 ($105,592) and Tract 23 ($69,896). 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 21.05?
The 2020-2024 American Community Survey puts Census Tract 21.05's population at 2,308 (±290) in 1,308 households; the 2020 Census counted 2,184 residents and 2,484 housing units.
| Measure | Tract 21.05 | Seabrook Island |
|---|---|---|
| Total population | 2,308 ±290 | 2,204 |
| Households | 1,308 ±183 | 1,250 |
| Average household size | 1.76 ±0.09 | 1.76 |
| Housing units | 2,632 ±227 | 2,574 |
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 21.05?
The median resident of Census Tract 21.05 is 69.1 years old. The largest group is non-Hispanic white residents at 96.3%, then Hispanic or Latino residents (of any race) at 1.7%. 2.2% of residents were born outside the United States.
| Measure | Tract 21.05 | Seabrook Island |
|---|---|---|
| Median age | 69.1 ±1.7 | 68.9 |
| Under 18 years | 0.3% ±0.4 pts | 0.3% |
| 65 years and over | 63.8% ±5.4 pts | 63.5% |
| Hispanic or Latino (any race) | 1.7% ±1.6 pts | 1.8% |
| White alone, not Hispanic | 96.3% ±1.9 pts | 96.1% |
| Black or African American alone, not Hispanic | 0.2% ±0.4 pts | 0.2% |
| Asian alone, not Hispanic | 0.6% ±0.8 pts | 0.6% |
| American Indian and Alaska Native alone, not Hispanic | 0.0% ±0.1 pts | 0.0% |
| Native Hawaiian and Other Pacific Islander alone, not Hispanic | 0.0% ±1.9 pts | 0.0% |
| Two or more races, not Hispanic | 1.2% ±0.8 pts | 1.2% |
| Some other race alone, not Hispanic | 0.0% ±1.9 pts | 0.0% |
| Born outside the United States | 2.2% ±1.2 pts | 2.3% |
| Speak a language other than English at home (age 5+) | 3.7% ±2.2 pts | 3.9% |
| Civilian veterans (age 18+) | 7.8% ±2.2 pts | 8.2% |
| With a disability | 7.5% ±2.3 pts | 7.4% |
| No health insurance coverage | 1.3% ±0.9 pts | 1.4% |
| High school graduate or higher (age 25+) | 99.6% ±0.7 pts | 99.6% |
| Bachelor's degree or higher (age 25+) | 78.2% ±4.4 pts | 78.4% |
| Graduate or professional degree (age 25+) | 38.3% ±4.7 pts | 38.1% |
| Lived in the same house a year earlier | 87.0% ±4.0 pts | 86.4% |
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 21.05 earn?
Half of the 1,308 households in Census Tract 21.05 earn less than $132,188 a year (±$32,027), against $88,494 across Charleston County: 17th highest of the county's 93 tracts with a reliable estimate.
| Measure | Tract 21.05 | Seabrook Island |
|---|---|---|
| Median household income | $132,188 ±$32,027 | $127,500 |
| Mean household income | $241,284 ±$38,797 | $229,809 |
| Per capita income | $139,730 ±$21,828 | $132,020 |
| People below the poverty line | 4.2% ±3.6 pts | 4.4% |
| Children under 18 below the poverty line | 0.0% ±100.0 pts | 0.0% |
| Households receiving SNAP | 0.0% ±3.4 pts | 0.0% |
| Households with a computer | 99.7% ±0.5 pts | 99.7% |
| Households with a broadband subscription | 98.9% ±1.0 pts | 98.9% |
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 21.05?
Owners occupy 95.9% of Census Tract 21.05's occupied homes and renters 4.1%. The median owner-occupied home is valued at $1,029,400 by its owner (±$86,565). The median renter pays $3,500 or more a month including utilities.
| Measure | Tract 21.05 | Seabrook Island |
|---|---|---|
| Median home value (owner-occupied) | $1,029,400 ±$86,565 | $1,001,400 |
| Median gross rent | $3,500 or more | $3,500 or more |
| Renters paying 35% or more of income on rent | 48.6% ±45.8 pts | 48.6% |
| Median monthly owner costs, with a mortgage | $3,614 ±$310 | $3,543 |
| Owner-occupied homes | 95.9% ±2.4 pts | 95.8% |
| Renter-occupied homes | 4.1% ±2.4 pts | 4.2% |
| Housing units | 2,632 ±227 | 2,574 |
| Single-family detached homes | 59.1% ±5.6 pts | 58.2% |
| Mobile homes | 0.0% ±1.7 pts | 0.0% |
| Built 2020 or later | 3.1% ±1.3 pts | 2.5% |
| Built 2010 to 2019 | 10.0% ±3.8 pts | 9.2% |
| Built 1939 or earlier | 0.4% ±0.4 pts | 0.4% |
| Households with no vehicle | 1.6% ±2.3 pts | 1.7% |
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 21.05 get to work?
46.1% of Census Tract 21.05's workers drive alone and 46.9% work from home. The average trip to work takes 28.2 minutes.
| Measure | Tract 21.05 | Seabrook Island |
|---|---|---|
| In the labor force (age 16+) | 33.6% ±5.0 pts | 34.2% |
| Unemployment rate | 0.0% ±5.7 pts | 0.0% |
| Drove alone to work | 46.1% ±10.2 pts | 47.4% |
| Carpooled | 2.4% ±2.1 pts | 2.4% |
| Public transportation | 0.0% ±5.7 pts | 0.0% |
| Walked | 2.2% ±2.5 pts | 2.3% |
| Worked from home | 46.9% ±9.6 pts | 45.4% |
| Mean travel time to work | 28.2 min ±5.7 | 28.2 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 21.05 compare with the other tracts in Charleston County?
Among Charleston County's tracts with a reliable estimate, Census Tract 21.05 ranks as shown below (1 = highest).
| Measure | In Charleston County |
|---|---|
| Population | 76th of 98 |
| Residents per square mile | 86th of 98 |
| Median household income | 17th of 93 |
| Per capita income | 4th of 97 |
| Median home value | 10th of 92 |
| Median gross rent | 1st of 86 |
| Bachelor's degree or higher | 7th of 96 |
| Median age | 1st of 98 |
| Owner-occupied share | 4th of 97 |
The tracts next to it on Charleston County's income ladder
| Tract | Rank | Median household income |
|---|---|---|
| Tract 30 | 14th | $133,350±$18,733 · within the margin of this tract |
| Tract 46.14 | 15th | $133,235±$19,052 · within the margin of this tract |
| Tract 21.06 | 16th | $132,692±$50,530 · within the margin of this tract |
| Tract 21.05 | 17th | $132,188±$32,027 |
| Tract 46.19 | 18th | $120,722±$31,347 · within the margin of this tract |
| Tract 28.02 | 19th | $119,792±$26,241 · within the margin of this tract |
| Tract 20.05 | 20th | $119,464±$19,275 · 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 21.05?
4 of the 18 figures for Census Tract 21.05 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