Census tract · Middlesex County
Census Tract 3688, Middlesex County, Massachusetts
Census Tract 3688, GEOID 25017368800, in Middlesex County, Massachusetts, entirely within Waltham. 5,630 residents in the ACS 2020-2024 5-year estimates (±588); the 2020 Census counted 6,169.
Residents, 2020-2024
5,630
±588 (90% margin)
2020 Census count: 6,169
Median household income
$104,608
±$24,622 (90% margin)
Middlesex County: $130,847
Median home value
$792,400
±$57,632 (90% margin)
Middlesex County: $727,800
Median gross rent
$2,490
±$343 (90% margin)
Middlesex County: $2,201
Where is Census Tract 3688?
Census Tract 3688 is one of 357 census tracts in Middlesex County, Massachusetts. It covers 0.65 square miles of land, 9,476 residents per square mile in 2020. Its GEOID, 25017368800, names it uniquely (how tract numbers and GEOIDs work).
| Place | Share of the tract |
|---|---|
| Waltham | 100% |
8 census tracts border Census Tract 3688: Tract 3683 ($91,955), Tract 3684 ($131,250), Tract 3685 ($93,182), Tract 3687, Tract 3689.02 ($58,887), Tract 3691 ($133,824), Tract 3701.04 ($127,455) and Tract 3745 ($141,892). 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 3688?
The 2020-2024 American Community Survey puts Census Tract 3688's population at 5,630 (±588) in 2,701 households; the 2020 Census counted 6,169 residents and 2,831 housing units.
| Measure | Tract 3688 | Waltham |
|---|---|---|
| Total population | 5,630 ±588 | 64,902 |
| Households | 2,701 ±278 | 25,498 |
| Average household size | 2.02 ±0.15 | 2.23 |
| Housing units | 2,879 ±242 | 26,728 |
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 3688?
The median resident of Census Tract 3688 is 39.2 years old; 13.2% are under 18 and 19.3% are 65 or older. The largest group is non-Hispanic white residents at 51.9%, then Hispanic or Latino residents (of any race) at 16.2%. 38.4% of residents were born outside the United States.
| Measure | Tract 3688 | Waltham |
|---|---|---|
| Median age | 39.2 ±5.3 | 34.4 |
| Under 18 years | 13.2% ±2.7 pts | 13.6% |
| 65 years and over | 19.3% ±3.5 pts | 15.8% |
| Hispanic or Latino (any race) | 16.2% ±9.2 pts | 15.9% |
| White alone, not Hispanic | 51.9% ±9.4 pts | 57.6% |
| Black or African American alone, not Hispanic | 8.9% ±5.9 pts | 8.3% |
| Asian alone, not Hispanic | 15.7% ±7.4 pts | 12.6% |
| American Indian and Alaska Native alone, not Hispanic | 0.0% ±0.8 pts | 0.3% |
| Native Hawaiian and Other Pacific Islander alone, not Hispanic | 0.0% ±0.8 pts | 0.1% |
| Two or more races, not Hispanic | 6.5% ±4.0 pts | 4.3% |
| Some other race alone, not Hispanic | 0.7% ±1.2 pts | 0.9% |
| Born outside the United States | 38.4% ±8.9 pts | 26.3% |
| Speak a language other than English at home (age 5+) | 40.5% ±10.2 pts | 32.3% |
| Civilian veterans (age 18+) | 1.9% ±1.3 pts | 2.6% |
| With a disability | 15.2% ±4.8 pts | 10.7% |
| No health insurance coverage | 6.8% ±3.7 pts | 2.9% |
| High school graduate or higher (age 25+) | 91.9% ±5.0 pts | 93.3% |
| Bachelor's degree or higher (age 25+) | 57.2% ±9.5 pts | 57.3% |
| Graduate or professional degree (age 25+) | 33.7% ±7.7 pts | 27.9% |
| Lived in the same house a year earlier | 78.9% ±4.7 pts | 83.0% |
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 3688 earn?
Half of the 2,701 households in Census Tract 3688 earn less than $104,608 a year (±$24,622), against $130,847 across Middlesex County: 265th highest of the county's 350 tracts with a reliable estimate. 10.2% of residents live below the poverty line.
| Measure | Tract 3688 | Waltham |
|---|---|---|
| Median household income | $104,608 ±$24,622 | $120,216 |
| Mean household income | $142,889 ±$24,467 | $145,664 |
| Per capita income | $69,316 ±$11,266 | $58,449 |
| People below the poverty line | 10.2% ±5.2 pts | 9.4% |
| Children under 18 below the poverty line | 6.2% ±10.5 pts | 7.6% |
| Households receiving SNAP | 5.5% ±3.3 pts | 7.0% |
| Households with a computer | 94.1% ±4.3 pts | 95.6% |
| Households with a broadband subscription | 94.0% ±4.7 pts | 94.0% |
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 3688?
Owners occupy 39.5% of Census Tract 3688's occupied homes and renters 60.5%. The median owner-occupied home is valued at $792,400 by its owner (±$57,632). The median renter pays $2,490 a month including utilities, and 21.5% of renters pay 35% or more of their income on rent.
| Measure | Tract 3688 | Waltham |
|---|---|---|
| Median home value (owner-occupied) | $792,400 ±$57,632 | $748,700 |
| Median gross rent | $2,490 ±$343 | $2,268 |
| Renters paying 35% or more of income on rent | 21.5% ±10.0 pts | 35.7% |
| Median monthly owner costs, with a mortgage | $3,182 ±$416 | $3,076 |
| Owner-occupied homes | 39.5% ±8.4 pts | 49.7% |
| Renter-occupied homes | 60.5% ±8.4 pts | 50.3% |
| Housing units | 2,879 ±242 | 26,728 |
| Single-family detached homes | 22.4% ±6.2 pts | 37.0% |
| Mobile homes | 0.0% ±1.5 pts | 0.2% |
| Built 2020 or later | 0.5% ±0.8 pts | 1.1% |
| Built 2010 to 2019 | 19.4% ±6.6 pts | 6.4% |
| Built 1939 or earlier | 31.3% ±7.9 pts | 28.3% |
| Households with no vehicle | 12.8% ±5.0 pts | 8.6% |
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 3688 get to work?
58.6% of Census Tract 3688's workers drive alone and 26.8% work from home. The average trip to work takes 26.2 minutes.
| Measure | Tract 3688 | Waltham |
|---|---|---|
| In the labor force (age 16+) | 72.8% ±6.2 pts | 68.5% |
| Unemployment rate | 3.2% ±3.0 pts | 3.7% |
| Drove alone to work | 58.6% ±7.2 pts | 53.0% |
| Carpooled | 5.5% ±3.8 pts | 9.5% |
| Public transportation | 2.9% ±1.8 pts | 4.5% |
| Walked | 5.0% ±5.1 pts | 6.2% |
| Worked from home | 26.8% ±9.6 pts | 24.2% |
| Mean travel time to work | 26.2 min ±4.2 | 24.7 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 3688 compare with the other tracts in Middlesex County?
Among Middlesex County's tracts with a reliable estimate, Census Tract 3688 ranks as shown below (1 = highest).
| Measure | In Middlesex County | In Waltham |
|---|---|---|
| Population | 100th of 354 | 5th of 13 |
| Residents per square mile | 120th of 357 | 4th of 13 |
| Median household income | 265th of 350 | 8th of 11 |
| Per capita income | 165th of 354 | 4th of 13 |
| Median home value | 151st of 350 | 5th of 13 |
| Median gross rent | 108th of 327 | 3rd of 12 |
| Poverty rate | 92nd of 223 | 6th of 9 |
| Bachelor's degree or higher | 204th of 354 | 6th of 13 |
| Median age | 193rd of 354 | 5th of 13 |
| Owner-occupied share | 273rd of 351 | 10th of 13 |
The tracts next to it on Middlesex County's income ladder
| Tract | Rank | Median household income |
|---|---|---|
| Tract 3335.02 | 262nd | $105,313±$37,637 · within the margin of this tract |
| Tract 3154.01 | 263rd | $104,913±$13,215 · within the margin of this tract |
| Tract 3840.03 | 264th | $104,837±$27,147 · within the margin of this tract |
| Tract 3688 | 265th | $104,608±$24,622 |
| Tract 3216 | 266th | $104,375±$16,858 · within the margin of this tract |
| Tract 3364.02 | 267th | $104,327±$46,371 · within the margin of this tract |
| Tract 3546.02 | 268th | $104,155±$19,201 · 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 3688?
1 of the 18 figures for Census Tract 3688 on this page carries a coefficient of variation over 40% and is 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