Town · Massachusetts
Merrimac, Massachusetts
Merrimac, town, in Essex County, Massachusetts. Merrimac had 6,818 residents on July 1, 2025 by the Census Bureau's estimate, up 1.4% since 2020; the 2020 Census counted 6,723 and the ACS 2020-2024 5-year estimates put it at 6,748 (±17). GEOID 2500940430.
Residents, July 2025 estimate
6,818
Census Bureau estimate (no margin published)
2020 Census count: 6,723 · ACS 2020-2024: 6,748 ±17
Median household income
$123,054
±$16,062 (90% margin)
Massachusetts: $103,960
Median home value
$553,400
±$37,584 (90% margin)
Massachusetts: $562,100
Median gross rent
$1,352
±$325 (90% margin)
Massachusetts: $1,762
Where is Merrimac and what county is it in?
Merrimac is a town in Essex County, Massachusetts. It covers 8.5 square miles of land, 791 residents per square mile in 2020.
Merrimac is in the Boston-Cambridge-Newton, MA-NH metropolitan statistical area, which takes in 7 counties (Census Bureau delineation, July 2023).
Merrimac is the same area as Census Tract 2621 of Essex County: the tract's figures are Merrimac's own.
Source: 2024 Gazetteer and 2020 place-by-county files, U.S. Census Bureau · Census reference files
How many people live in Merrimac, and is it growing?
The Census Bureau estimates that 6,818 people lived in Merrimac on July 1, 2025, up 1.4% since 2020, in line with Massachusetts (+1.7%). The 2020 Census counted 6,723 residents. The 2020-2024 American Community Survey, a five-year sample, puts the population at 6,748 (±17).
| Measure | Merrimac | Essex County | Change since 2015-2019 |
|---|---|---|---|
| Total population | 6,748±17 | 813,054 | −142 |
| Households | 2,815±266 | 313,147 | no clear change |
| Average household size | 2.39±0.22 | 2.54 | no clear change |
| Housing units | 2,899±271 | 329,776 | no clear change |
Merrimac's population since 2000
From 6,138 in 2000 to 6,818 in 2025: up 11.1%. The 2000, 2010 and 2020 figures are census counts, each for Merrimac as it was drawn that year: a place that annexed land, or a community that has since incorporated, covered a different area then. The 2005 figure is the Census Bureau's intercensal estimate, revised to fit the 2000 and 2010 counts and drawn on 2010 boundaries; 2015 and 2025 are July 1 estimates made from the census before them.
Source: The 2000, 2010 and 2020 Census counts and the Census Bureau's population estimates (intercensal 2000-2010, Vintage 2020, Vintage 2025) · Census population estimates
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 Merrimac?
The median resident of Merrimac is 49.4 years old; 16.5% are under 18 and 26.7% are 65 or older. The largest group is non-Hispanic white residents at 91.3%, then non-Hispanic residents of two or more races at 5.8%.
| Measure | Merrimac | Essex County | Change since 2015-2019 |
|---|---|---|---|
| Median age | 49.4±6.8 | 41.2 | no clear change |
| Under 18 years | 16.5%±4.1 pts | 20.8% | – |
| 65 years and over | 26.7%±5.2 pts | 18.5% | – |
| Male | 54.3%±4.6 pts | 48.6% | – |
| Hispanic or Latino (any race) | 2.4%±1.8 pts | 24.1% | – |
| White alone, not Hispanic | 91.3%±7.0 pts | 64.5% | no clear change |
| Black or African American alone, not Hispanic | 0.0%±0.6 pts | 3.5% | – |
| Asian alone, not Hispanic | 0.5%±0.7 pts | 3.5% | – |
| American Indian and Alaska Native alone, not Hispanic | 0.0%±0.6 pts | 0.0% | – |
| Native Hawaiian and Other Pacific Islander alone, not Hispanic | 0.0%±0.6 pts | 0.0% | – |
| Two or more races, not Hispanic | 5.8%±6.8 pts | 3.5% | – |
| Some other race alone, not Hispanic | 0.0%±0.6 pts | 0.8% | – |
| Born outside the United States | 1.5%±1.2 pts | 19.1% | – |
| Speak a language other than English at home (age 5+) | 2.7%±1.9 pts | 28.7% | – |
| Civilian veterans (age 18+) | 4.0%±1.6 pts | 4.3% | – |
| With a disability | 14.3%±3.9 pts | 12.3% | – |
| No health insurance coverage | 1.6%±1.3 pts | 2.8% | – |
| High school graduate or higher (age 25+) | 96.0%±2.4 pts | 90.1% | – |
| Bachelor's degree or higher (age 25+) | 41.0%±7.9 pts | 43.0% | no clear change |
| Graduate or professional degree (age 25+) | 13.2%±4.9 pts | 17.9% | – |
| Lived in the same house a year earlier | 91.4%±4.7 pts | 90.8% | – |
| Moved from another state in the past year | 2.4%±1.9 pts | 1.4% | – |
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 Merrimac earn?
Half of Merrimac's 2,815 households earn less than $123,054 a year (±$16,062), against $101,883 in Essex County and $103,960 in Massachusetts. In 2015-2019 it was $104,128 in 2024 dollars; the margins of error cannot tell the two periods apart.
| Measure | Merrimac | Essex County | Change since 2015-2019 |
|---|---|---|---|
| Median household income | $123,054±$16,062 | $101,883 | no clear change |
| Mean household income | $134,302±$12,782 | $140,098 | – |
| Per capita income | $57,070±$7,395 | $54,665 | no clear change |
| People below the poverty line | 9.4%±7.6 pts | 9.4% | – |
| Children under 18 below the poverty line | 24.3%±26.4 pts | 11.9% | – |
| Households receiving SNAP | 14.3%±7.5 pts | 16.6% | – |
| Households with a computer | 96.5%±2.0 pts | 95.2% | – |
| Households with a broadband subscription | 91.3%±4.7 pts | 92.4% | – |
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 Merrimac?
Owners occupy 81.3% of Merrimac's occupied homes and renters 18.7%. The median owner-occupied home is valued at $553,400 by its owner (±$37,584). The median renter pays $1,352 a month including utilities.
| Measure | Merrimac | Essex County | Change since 2015-2019 |
|---|---|---|---|
| Median home value (owner-occupied) | $553,400±$37,584 | $619,100 | +$107,150 |
| Median gross rent | $1,352±$325 | $1,756 | no clear change |
| Renters paying 35% or more of income on rent | 13.7%±10.9 pts | 46.4% | – |
| Median monthly owner costs, with a mortgage | $2,571±$240 | $2,867 | – |
| Owner-occupied homes | 81.3%±7.6 pts | 63.5% | no clear change |
| Renter-occupied homes | 18.7%±7.6 pts | 36.5% | – |
| Housing units | 2,899±271 | 329,776 | no clear change |
| Homeowner vacancy rate | 0.0%±1.8 pts | 0.3% | – |
| Rental vacancy rate | 6.2%±10.1 pts | 2.6% | – |
| Single-family detached homes | 61.7%±7.5 pts | 49.6% | – |
| Mobile homes | 6.9%±3.0 pts | 0.4% | – |
| Built 2020 or later | 3.8%±2.7 pts | 0.7% | – |
| Built 2010 to 2019 | 5.9%±2.8 pts | 5.2% | – |
| Built 1939 or earlier | 19.5%±6.1 pts | 34.6% | – |
| Households with no vehicle | 3.0%±1.9 pts | 9.3% | – |
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 many new homes is Merrimac building?
Builders took permits for 36 new housing units in Merrimac in 2025 (36 in single-family houses), 5.3 per 1,000 residents against 1.7 across Massachusetts.
Counts of units in permits a local office issued; not every permitted unit is built. A year marked with months was reported for part of the year.
Source: Building Permits Survey, annual place files 2019-2025, U.S. Census Bureau · Census Building Permits Survey
How do people in Merrimac work and get to work?
86.3% of Merrimac's workers drive alone and 8.5% work from home. The average trip to work takes 32.0 minutes.
| Measure | Merrimac | Essex County | Change since 2015-2019 |
|---|---|---|---|
| In the labor force (age 16+) | 69.2%±4.5 pts | 67.5% | – |
| Unemployment rate | 1.5%±1.4 pts | 5.1% | – |
| Drove alone to work | 86.3%±5.0 pts | 67.6% | – |
| Carpooled | 1.1%±1.1 pts | 7.3% | – |
| Public transportation | 2.0%±2.9 pts | 3.5% | – |
| Walked | 1.5%±1.2 pts | 2.7% | – |
| Worked from home | 8.5%±3.5 pts | 16.4% | no clear change |
| Mean travel time to work | 32.0 min±4.1 | 28.5 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 Merrimac?
1 census tract lies mostly in Merrimac (2020 census blocks).
| Tract | Residents, 2020-2024 | Median household income |
|---|---|---|
| Tract 2621Essex County | 6,748 | $123,054 |
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 Merrimac) · Census block assignment files
How does Merrimac compare with other places in Massachusetts?
By the Census Bureau's July 2025 estimates, Merrimac is the 1,758th-most populous of the 16,079 U.S. towns and townships that have one and the 141st-most populous of 266 in Massachusetts.
Merrimac ranks 169th of 453 places in Massachusetts with 1,000 or more residents and a reliable estimate, by median household income.
| Measure | Rank | Of |
|---|---|---|
| Population, July 2025 estimate | 141st | 266 |
| Growth 2020-2025 (PEP) | 157th | 292 |
| Residents per square mile | 239th | 461 |
| Median household income | 169th | 453 |
| Per capita income | 215th | 460 |
| Median home value | 205th | 459 |
| Median gross rent | 269th | 410 |
| Bachelor's degree or higher | 289th | 459 |
| Median age | 126th | 461 |
| Owner-occupied share | 216th | 460 |
| Work from home | 391st | 429 |
| Travel time to work | 158th | 459 |
Merrimac's figures with every place in Massachusetts (CSV)
Every place in Massachusetts, sortable · Compare Merrimac 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 Merrimac?
21 of the 57 figures for Merrimac 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 Merrimac 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.