PlainCities

Census tract · Middlesex County

Census Tract 3631.05, Middlesex County, Massachusetts

Census Tract 3631.05, GEOID 25017363105, in Middlesex County, Massachusetts, entirely within Acton. 4,210 residents in the ACS 2020-2024 5-year estimates (±808); the 2020 Census counted 3,781.

Residents, 2020-2024

4,210

±808 (90% margin)
2020 Census count: 3,781

Median household income

$125,833

±$38,250 (90% margin)
Middlesex County: $130,847

Median home value

$952,900

±$70,733 (90% margin)
Middlesex County: $727,800

Median gross rent

$1,956

±$206 (90% margin)
Middlesex County: $2,201

Where is Census Tract 3631.05?

Census Tract 3631.05 is one of 357 census tracts in Middlesex County, Massachusetts. It covers 3.38 square miles of land, 1,120 residents per square mile in 2020. Its GEOID, 25017363105, names it uniquely (how tract numbers and GEOIDs work).

Places Census Tract 3631.05 lies in (share of its 2020 census blocks)
PlaceShare of the tract
Acton100%
Census Tract 3631.05 (marked with a dot) in Middlesex County, Massachusetts. Boundaries: Census Bureau 2024.
361336213631.043631.06 3631.05 2 mi
Census Tract 3631.05 (shaded) and the tracts that border it, numbered. Boundaries: Census Bureau 2024 cartographic boundary file, 1:500,000.

4 census tracts border Census Tract 3631.05: Tract 3613 ($211,161), Tract 3621 ($250,000 or more), Tract 3631.04 ($155,150) and Tract 3631.06 ($107,150). 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 3631.05?

The 2020-2024 American Community Survey puts Census Tract 3631.05's population at 4,210 (±808) in 1,570 households; the 2020 Census counted 3,781 residents and 1,549 housing units.

Counts, ACS 2020-2024 5-year estimates
MeasureTract 3631.05ActonMiddlesex CountyMassachusetts
Total population4,210±80824,1551,638,3657,044,056
Households1,570±2419,409634,2152,785,042
Average household size2.61±0.312.552.492.44
Housing units1,654±2289,575664,2673,030,406

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 3631.05?

The median resident of Census Tract 3631.05 is 41.6 years old; 27.1% are under 18 and 16.2% are 65 or older. The largest group is non-Hispanic white residents at 43.9%, then non-Hispanic Asian residents at 23.7%. 38.6% of residents were born outside the United States.

Age, origin, education, ACS 2020-2024 5-year estimates. Race groups are non-Hispanic; Hispanic includes any race.
MeasureTract 3631.05ActonMiddlesex CountyMassachusetts
Median age41.6±3.944.538.940.0
Under 18 years27.1%±6.8 pts23.2%19.5%19.4%
65 years and over16.2%±4.2 pts17.6%16.3%17.9%
Hispanic or Latino (any race)3.8%±3.3 pts4.1%9.3%13.3%
White alone, not Hispanic43.9%±12.6 pts58.9%65.1%66.6%
Black or African American alone, not Hispanic19.6%±18.3 pts4.7%4.7%6.4%
Asian alone, not Hispanic23.7%±6.0 pts25.5%13.6%7.3%
American Indian and Alaska Native alone, not Hispanic0.0%±1.0 pts0.0%0.1%0.1%
Native Hawaiian and Other Pacific Islander alone, not Hispanic0.0%±1.0 pts0.0%0.0%0.0%
Two or more races, not Hispanic8.7%±8.0 pts5.2%5.8%5.1%
Some other race alone, not Hispanic0.3%±0.5 pts1.7%1.4%1.2%
Born outside the United States38.6%±7.9 pts28.8%23.1%18.0%
Speak a language other than English at home (age 5+)50.9%±14.7 pts34.1%29.1%25.1%
Civilian veterans (age 18+)1.9%±1.9 pts4.4%3.3%4.3%
With a disability6.9%±3.5 pts9.1%9.9%12.3%
No health insurance coverage4.3%±4.2 pts1.7%2.4%2.6%
High school graduate or higher (age 25+)96.5%±2.6 pts98.0%93.2%91.4%
Bachelor's degree or higher (age 25+)74.3%±7.3 pts79.5%59.5%47.3%
Graduate or professional degree (age 25+)39.2%±8.8 pts47.6%30.5%21.8%
Lived in the same house a year earlier75.5%±17.7 pts87.9%87.2%88.3%

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 3631.05 earn?

Half of the 1,570 households in Census Tract 3631.05 earn less than $125,833 a year (±$38,250), against $130,847 across Middlesex County: 195th highest of the county's 350 tracts with a reliable estimate.

Income and poverty in 2024 dollars, ACS 2020-2024 5-year estimates
MeasureTract 3631.05ActonMiddlesex CountyMassachusetts
Median household income$125,833±$38,250$158,230$130,847$103,960
Mean household income$205,731±$42,561$208,786$178,070$144,950
Per capita income$77,157±$18,403$81,425$69,556$57,897
People below the poverty line4.4%±3.0 pts3.4%7.7%10.0%
Children under 18 below the poverty line2.1%±2.7 pts1.9%7.9%11.7%
Households receiving SNAP3.4%±3.4 pts3.9%9.3%14.7%
Households with a computer100.0%±2.7 pts98.3%97.0%95.7%
Households with a broadband subscription97.3%±3.3 pts97.2%94.7%92.8%

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 3631.05?

Owners occupy 56.1% of Census Tract 3631.05's occupied homes and renters 43.9%. The median owner-occupied home is valued at $952,900 by its owner (±$70,733). The median renter pays $1,956 a month including utilities, and 64.8% of renters pay 35% or more of their income on rent.

Housing, ACS 2020-2024 5-year estimates
MeasureTract 3631.05ActonMiddlesex CountyMassachusetts
Median home value (owner-occupied)$952,900±$70,733$807,300$727,800$562,100
Median gross rent$1,956±$206$1,986$2,201$1,762
Renters paying 35% or more of income on rent64.8%±20.0 pts44.0%37.6%41.8%
Median monthly owner costs, with a mortgage$4,000 or more$3,812$3,224$2,726
Owner-occupied homes56.1%±10.1 pts74.9%61.3%62.5%
Renter-occupied homes43.9%±10.1 pts25.1%38.7%37.5%
Housing units1,654±2289,575664,2673,030,406
Single-family detached homes45.9%±9.0 pts63.3%46.5%51.1%
Mobile homes0.0%±2.5 pts0.0%0.4%0.8%
Built 2020 or later0.0%±2.5 pts0.4%1.2%1.0%
Built 2010 to 20192.6%±2.6 pts6.5%7.3%6.2%
Built 1939 or earlier5.0%±4.4 pts8.8%32.3%30.5%
Households with no vehicle2.6%±3.0 pts3.1%10.3%11.7%

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 3631.05 get to work?

61.9% of Census Tract 3631.05's workers drive alone and 22.3% work from home. The average trip to work takes 35.8 minutes.

Work and commuting, ACS 2020-2024 5-year estimates
MeasureTract 3631.05ActonMiddlesex CountyMassachusetts
In the labor force (age 16+)70.9%±6.7 pts69.7%69.9%67.0%
Unemployment rate12.2%±8.1 pts4.7%4.4%5.2%
Drove alone to work61.9%±9.7 pts52.7%54.2%61.2%
Carpooled9.0%±6.7 pts5.2%6.3%7.0%
Public transportation3.8%±3.2 pts3.3%7.2%6.5%
Walked2.1%±2.2 pts2.0%4.2%4.1%
Worked from home22.3%±9.4 pts35.9%24.7%18.6%
Mean travel time to work35.8 min±5.934.6 min29.9 min29.1 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 3631.05 compare with the other tracts in Middlesex County?

Among Middlesex County's tracts with a reliable estimate, Census Tract 3631.05 ranks as shown below (1 = highest).

Census Tract 3631.05's rank among the tracts of Middlesex County
MeasureIn Middlesex County
Population200th of 354
Residents per square mile302nd of 357
Median household income195th of 350
Per capita income121st of 354
Median home value82nd of 350
Median gross rent213th of 327
Bachelor's degree or higher107th of 354
Median age144th of 354
Owner-occupied share202nd of 351

The tracts next to it on Middlesex County's income ladder

Median household income, ACS 2020-2024 5-year estimates
TractRankMedian household incomeResidents
Tract 3322.02192nd$126,641±$21,150 · within the margin of this tract6,841
Tract 3011.02193rd$126,549±$9,821 · within the margin of this tract5,085
Tract 3417194th$126,250±$45,828 · within the margin of this tract6,059
Tract 3631.05195th$125,833±$38,2504,210
Tract 3372.02196th$125,766±$32,460 · within the margin of this tract4,935
Tract 3686197th$125,625±$16,661 · within the margin of this tract5,688
Tract 3336.01198th$125,278±$52,229 · within the margin of this tract2,251

"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 3631.05?

3 of the 18 figures for Census Tract 3631.05 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