Census-designated place · Massachusetts
South Dennis, Massachusetts
South Dennis, census-designated place, in Barnstable County, Massachusetts. South Dennis had 3,899 residents in the 2020 Census, a full count; the ACS 2020-2024 5-year estimates put it at 3,135 (±428). GEOID 2563655.
Residents, 2020 Census
3,899
Census count or controlled total
ACS 2020-2024 estimate: 3,135 ±428
Median household income
$88,411
±$12,702 (90% margin)
Massachusetts: $103,960
Median home value
$495,700
±$36,050 (90% margin)
Massachusetts: $562,100
Median gross rent
$2,003
±$1,005 (90% margin)
Massachusetts: $1,762
Where is South Dennis and what county is it in?
South Dennis is a census-designated place: an unincorporated community the Census Bureau draws for counting, with no city government of its own, in Barnstable County, Massachusetts. It covers 4.6 square miles of land, 857 residents per square mile in 2020.
South Dennis is in the Barnstable Town, MA metropolitan statistical area (Census Bureau delineation, July 2023).
South Dennis lies entirely within Dennis, a town with its own local government (2020 census blocks).
Source: 2024 Gazetteer and 2020 place-by-county files, U.S. Census Bureau · Census reference files
How many people live in South Dennis, and is it growing?
The 2020 Census counted 3,899 residents in South Dennis, a full count rather than a sample. The 2020-2024 American Community Survey, a sample, estimates 3,135 (±428).
The Census Bureau publishes yearly population estimates for incorporated places only; South Dennis is a census-designated place, so its figures come from the ACS and the 2020 Census.
| Measure | South Dennis | Barnstable County | Change since 2015-2019 |
|---|---|---|---|
| Total population | 3,135 ±428 | 231,668 | no clear change |
| Households | 1,597 ±233 | 105,777 | no clear change |
| Average household size | 1.92 ±0.15 | 2.16 | no clear change |
| Housing units | 2,616 ±265 | 166,215 | no clear change |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026); Census PEP Vintage 2025 (SUB-EST2025, CO-EST2025); 2020 Census P.L. 94-171 · Check it at data.census.gov
Who lives in South Dennis?
The median resident of South Dennis is 57.6 years old; 10.4% are under 18 and 35.8% are 65 or older. The largest group is non-Hispanic white residents at 91.4%, then non-Hispanic Black residents at 4.7%.
| Measure | South Dennis | Barnstable County | Change since 2015-2019 |
|---|---|---|---|
| Median age | 57.6 ±2.7 | 55.4 | no clear change |
| Under 18 years | 10.4% ±3.5 pts | 14.1% | – |
| 65 years and over | 35.8% ±5.7 pts | 33.1% | – |
| Male | 52.4% ±4.0 pts | 48.1% | – |
| Hispanic or Latino (any race) | 0.4% ±0.7 pts | 3.7% | – |
| White alone, not Hispanic | 91.4% ±7.2 pts | 85.2% | no clear change |
| Black or African American alone, not Hispanic | 4.7% ±6.2 pts | 2.8% | – |
| Asian alone, not Hispanic | 0.5% ±0.6 pts | 1.5% | – |
| American Indian and Alaska Native alone, not Hispanic | 0.0% ±1.3 pts | 0.3% | – |
| Native Hawaiian and Other Pacific Islander alone, not Hispanic | 0.0% ±1.3 pts | 0.0% | – |
| Two or more races, not Hispanic | 0.0% ±1.3 pts | 5.2% | – |
| Some other race alone, not Hispanic | 3.0% ±4.0 pts | 1.3% | – |
| Born outside the United States | 6.0% ±5.2 pts | 9.9% | – |
| Speak a language other than English at home (age 5+) | 1.4% ±1.5 pts | 10.8% | – |
| Civilian veterans (age 18+) | 5.3% ±2.5 pts | 7.1% | – |
| With a disability | 13.0% ±3.8 pts | 14.8% | – |
| No health insurance coverage | 0.9% ±1.0 pts | 2.7% | – |
| High school graduate or higher (age 25+) | 97.5% ±1.8 pts | 96.2% | – |
| Bachelor's degree or higher (age 25+) | 43.3% ±7.1 pts | 48.2% | +11.8 pts |
| Graduate or professional degree (age 25+) | 14.3% ±4.5 pts | 22.4% | – |
| Lived in the same house a year earlier | 95.6% ±2.5 pts | 90.8% | – |
| Moved from another state in the past year | 1.6% ±1.7 pts | 2.7% | – |
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 South Dennis earn?
Half of South Dennis's 1,597 households earn less than $88,411 a year (±$12,702), against $95,241 in Barnstable County and $103,960 in Massachusetts. In 2015-2019 it was $73,796 in 2024 dollars; the margins of error cannot tell the two periods apart.
| Measure | South Dennis | Barnstable County | Change since 2015-2019 |
|---|---|---|---|
| Median household income | $88,411 ±$12,702 | $95,241 | no clear change |
| Mean household income | $99,225 ±$11,629 | $134,349 | – |
| Per capita income | $49,995 ±$5,552 | $62,086 | +$8,485 |
| People below the poverty line | 3.0% ±2.0 pts | 7.7% | – |
| Children under 18 below the poverty line | 0.0% ±12.2 pts | 9.1% | – |
| Households receiving SNAP | 11.1% ±5.5 pts | 9.4% | – |
| Households with a computer | 96.0% ±3.9 pts | 96.5% | – |
| Households with a broadband subscription | 98.1% ±2.0 pts | 94.3% | – |
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 South Dennis?
Owners occupy 82.7% of South Dennis's occupied homes and renters 17.3%. The median owner-occupied home is valued at $495,700 by its owner (±$36,050). The median renter pays $2,003 a month including utilities.
| Measure | South Dennis | Barnstable County | Change since 2015-2019 |
|---|---|---|---|
| Median home value (owner-occupied) | $495,700 ±$36,050 | $629,000 | +$108,770 |
| Median gross rent | $2,003 ±$1,005 | $1,678 | no clear change |
| Renters paying 35% or more of income on rent | 20.2% ±19.0 pts | 48.8% | – |
| Median monthly owner costs, with a mortgage | $1,945 ±$194 | $2,432 | – |
| Owner-occupied homes | 82.7% ±7.9 pts | 81.1% | no clear change |
| Renter-occupied homes | 17.3% ±7.9 pts | 18.9% | – |
| Housing units | 2,616 ±265 | 166,215 | no clear change |
| Homeowner vacancy rate | 0.0% ±3.2 pts | 1.0% | – |
| Rental vacancy rate | 12.1% ±18.0 pts | 4.7% | – |
| Single-family detached homes | 86.5% ±5.1 pts | 81.6% | – |
| Mobile homes | 4.7% ±4.4 pts | 0.8% | – |
| Built 2020 or later | 0.3% ±0.6 pts | 0.8% | – |
| Built 2010 to 2019 | 2.1% ±2.3 pts | 4.1% | – |
| Built 1939 or earlier | 2.1% ±2.3 pts | 11.4% | – |
| Households with no vehicle | 1.2% ±1.4 pts | 5.4% | – |
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 South Dennis work and get to work?
77.1% of South Dennis's workers drive alone and 9.5% work from home. The average trip to work takes 24.7 minutes.
| Measure | South Dennis | Barnstable County | Change since 2015-2019 |
|---|---|---|---|
| In the labor force (age 16+) | 60.4% ±5.3 pts | 58.3% | – |
| Unemployment rate | 3.8% ±4.4 pts | 5.0% | – |
| Drove alone to work | 77.1% ±12.6 pts | 72.1% | – |
| Carpooled | 13.3% ±7.4 pts | 7.0% | – |
| Public transportation | 0.0% ±2.6 pts | 1.2% | – |
| Walked | 0.0% ±2.6 pts | 1.9% | – |
| Worked from home | 9.5% ±6.2 pts | 16.0% | no clear change |
| Mean travel time to work | 24.7 min ±3.9 | 24.8 min | no clear change |
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 census tracts are in South Dennis?
1 census tract lies mostly in South Dennis, and 1 more reaches into it (2020 census blocks).
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026); 2020 block assignment files (tract share = share of the tract's census blocks in South Dennis) · Census block assignment files
How does South Dennis compare with other places in Massachusetts?
South Dennis ranks 336th of 453 places in Massachusetts with 1,000 or more residents and a reliable estimate, by median household income.
| Measure | Rank | Of |
|---|---|---|
| Population (ACS 2020-2024) | 342nd | 460 |
| Residents per square mile | 219th | 461 |
| Median household income | 336th | 453 |
| Per capita income | 321st | 460 |
| Median home value | 249th | 459 |
| Median gross rent | 89th | 410 |
| Bachelor's degree or higher | 268th | 459 |
| Median age | 45th | 461 |
| Owner-occupied share | 193rd | 460 |
| Work from home | 381st | 429 |
| Travel time to work | 356th | 459 |
South Dennis's figures with every place in Massachusetts (CSV)
Every place in Massachusetts, sortable · Compare South Dennis with other places
Source: PlainCities ranks computed from the American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) and PEP Vintage 2025 · How ranks are computed
How reliable are the figures for South Dennis?
24 of the 57 figures for South Dennis 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.
The American Community Survey samples about one household in eight over five years, so every figure is an estimate with a 90% margin of error (shown under each value). A ring marks an estimate whose coefficient of variation is over 40%. A change is called only when the gap between the two periods is larger than their combined 90% margin (the square root of the sum of the two squared margins), the Census Bureau's test. 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 · ACS technical documentation
How these figures are made: methodology and release checks · reading a margin of error · every state · corrections
Not on this page: crime, weather and schools for South Dennis are other agencies' records. Crime: the FBI's Crime Data Explorer · climate: NOAA's U.S. Climate Normals · schools: the National Center for Education Statistics' school search.