- county
- FIPS 25017
- Largest town: Cambridge
Middlesex County, Massachusetts
Middlesex County had 1,668,956 residents in the Census Vintage 2024 estimate, on 817.9 square miles of land. It is the most populous of Massachusetts's 14 county-equivalents.
- Population
- 1,668,956
- #1 of 14 in Massachusetts · #20 in US
- Area
- 817.9 sq mi
- #3 of 14 in Massachusetts · #1,034 in US
- Density
- 2,041 / sq mi
- #2 of 14 in Massachusetts · #72 in US
- Median household income
- $123,288
- #2 of 14 in Massachusetts · #27 in US
Census Vintage 2024 estimates · SAIPE 2023 income · 2024 Gazetteer land area
Measure from here
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Middlesex County population, land area and income
Middlesex County had 1,668,956 residents in the Census Vintage 2024 estimate, on 817.9 square miles of land. It is the most populous of Massachusetts's 14 county-equivalents. That works out to 2,040.6 people per square mile, 21.2 times the US average of 96.3, and in the top tenth nationally.
The median county-equivalent in Massachusetts has 503,121 residents, so Middlesex County is 3.3 times that size.
Its SAIPE 2023 median household income of $123,288 is in the top tenth among 3,143 counties with an estimate.
National rank among 3,144
Population
1,668,956
20th of 3,144 (US)
Land area
818 sq mi
1034th of 3,144 (US)
Density
2,040.6 / sq mi
72nd of 3,144 (US)
Median household income
$123,288
27th of 3,143 (US)
Rank within Massachusetts (14)
Population
1,668,956
1st of 14 (MA)
Land area
818 sq mi
3rd of 14 (MA)
Density
2,040.6 / sq mi
2nd of 14 (MA)
Median household income
$123,288
2nd of 14 (MA)
How Middlesex County's population changed since 2020
Middlesex County gained 41,378 residents between the July 2020 and July 2024 estimates, a rise of 2.5%. That ranks 5th of 14 in Massachusetts for growth. The median Massachusetts county changed by +2.2%, and the state as a whole by +2.0%.
Since the April 2020 estimates base, Middlesex County recorded 68,325 births and 52,711 deaths, a natural change of +15,614. Net international migration added +82,104 and net domestic migration, people moving to or from other US counties, came to -60,913. The largest single component was international migration, which added 82,104 people.
Components of change, April 2020 to July 2024
- Births
- 68,325
- Deaths
- 52,711
- Net international migration
- +82,104
- Net domestic migration
- -60,913
- Change, July 2023 to July 2024
- +24,024
Where Middlesex County is
The Census internal point of Middlesex County is at 42.481700, -71.394900. It sits in UTM zone 19N. The map shades Massachusetts's 14 county-equivalents by population change from 2020 to 2024, darker for faster growth, with Middlesex County outlined. Dots are towns of 1,000+ people with residents in it.
- < -0.1%
- < +2.0%
- < +2.3%
- < +2.6%
- ≥ +2.6%
Orange pin: Middlesex County internal point. Dark pin: Boston.
Internal point
- Decimal
- 42.481700, -71.394900
- DMS
- 42°28'54.12"N 71°23'41.64"W
- UTM
- 19N 303157.8E 4706040.3N
- Geohash
- drt1xmecf
- Plus code
- 87JCFJJ4+M2
Towns in Middlesex County
13 incorporated places of 1,000+ people have residents in Middlesex County, 884,066 people together, or 53% of the county. Each figure counts only the part of the town inside Middlesex County; towns marked "part" extend into another county. The largest is Cambridge with 121,186.
- 01Cambridge121,186
- 02Lowell120,418
- 03Newton90,700
- 04Somerville82,149
- 05Framingham73,361
- 06Malden66,693
- 07Waltham65,849
- 08Medford59,898
- 09Everett51,825
- 10Woburn43,895
- 11Marlborough42,169
- 12Watertown35,985
- 13Melrose29,938
Counties bordering Middlesex County
The Census 2024 county adjacency file lists 5 neighbors for Middlesex County, including 1 across a state line. The most populous is Worcester County, MA, with 881,248 residents. Distances run between Census internal points in a straight line.
Distance to Boston and the nearest big city
Boston is 18.9 miles ESE of Middlesex County's internal point in a straight line. The nearest place of 100,000 or more is Lowell, MA (population 120,418), 11.5 miles away. The nearest place of 10,000 or more is Waltham, MA (population 65,849), 10.1 miles away.
Middlesex County FIPS code
The FIPS code of Middlesex County is 25017: state code 25 for Massachusetts plus county code 017. Use it as text, with the leading zero, when joining Census, BLS, or CDC county tables. SAIPE lists its 2023 median household income as $123,288.
Questions people ask
What is the population of Middlesex County, Massachusetts?
The Census Vintage 2024 estimate for July 1, 2024 is 1,668,956. That is up 41,378 people (2.5%) from the July 2020 estimate of 1,627,578.
What is the FIPS code of Middlesex County?
25017. The first two digits (25) are Massachusetts; the last three (017) identify the county.
What is the largest town in Middlesex County?
Cambridge, with 121,186 residents inside Middlesex County in 2024.
Which counties border Middlesex County?
5 county-equivalents border it in the Census 2024 adjacency file: Worcester County, MA; Essex County, MA; Suffolk County, MA; Norfolk County, MA; Hillsborough County, NH.
Sources and data as of
Data as of: Census Vintage 2024 population estimates, 2024 Gazetteer land area and internal points, SAIPE 2023 median household income.
- 01Census Vintage 2024 county population estimates
- 02Census 2024 Gazetteer, counties
- 03Census SAIPE 2023 state and county estimates
- 04Census Vintage 2024 subcounty population estimates
- 05Census 2024 county adjacency file
- 06Census 2024 cartographic boundary file, counties (1:5,000,000)
How every number is computed: methodology. Spotted a wrong figure? Report an error.