What is the largest city in Middlesex County, MA?

Cambridge is the largest city or town in Middlesex County, with about 118,796 residents.

How many ZIP codes are in Middlesex County?

Middlesex County includes 81 ZIP Code Tabulation Areas, including 01431, 01432, 01450, 01460, 01463.

What is the population of Middlesex County, MA?

About 1,638,365 people live in Middlesex County, based on American Community Survey 5-year estimates.

What counties border Middlesex County?

Middlesex County borders Worcester County, Essex County, Suffolk County, Norfolk County, Hillsborough County, NH.

Middlesex County, MA: Cities, ZIP Codes & Local Data

Population

1,638,365

Land area

818sq mi

People per sq mi

2,003

ZIP codes

81

Middlesex County at a glance

Middlesex County is about 2.2 times as dense as Massachusetts as a whole.
It is the most populous county in Massachusetts.
Households here earn a median of $130,847 a year, 26% more than the Massachusetts figure of $103,960.
A typical owner-occupied home is valued at $727,800 (29% above Massachusetts) and median rent is $2,201 a month.
The biggest population centers are Cambridge (118,796), Lowell (118,368) and Newton (89,044).

Local data for Middlesex County, MA

Counts from official public data

Housing and community stats

Middlesex County, MA, American Community Survey 2020-2024

Full profile

Median household income

$130,847

Poverty rate

7.7%

Median home value

$727,800

Prices +3.6% in a year

Median rent

$2,201/mo

Homeownership

61.3%

Bachelor's or higher

59.5%

Median age

38.9

Average commute

29.9 min

Largest reported origins and ancestries: Irish Americans (300,318), Italian Americans (198,782), German Americans (102,787).

Home values and rents Income, education and commute

Economy and federal money

Jobs, income, federal spending and pandemic loans

Details

Unemployment rate

4.0%

Aug 2026, -0.3 pts in a year

Average annual pay

$118,479

903,942 jobs, 2025

Income per person

$112,011

BEA, 2024

Federal spending

$27.4B

FY 2026, $16,790 per person

PPP loans

$5.5B

52,692 loans, 514,191 jobs reported

Campaign donations

$56.12M

Itemized, 2026 cycle

Economy Federal spending PPP loans

How people get to work

Middlesex County, MA, workers 16 and older. American Community Survey 5-year estimates

Drove alone54.2%
Carpooled6.3%
Public transit7.2%
Walked4.2%
Bicycle1.6%
Taxi, ride-hailing, motorcycle or other1.8%
Worked from home24.7%

Average one-way commute: 29.9 minutes for people who do not work from home.

Environment and hazard risk

Middlesex County, MA, from FEMA, NOAA and EPA

Full report

Natural hazard risk

Relatively High

Top: ice storm

Storm events since 1996

1,840

Most often thunderstorm wind

Flood insurance policies

4,000

1.0% of homes, county

July high / Jan low

85° / 18°F

42.6 inches of rain a year

Hazards, floods and storm history Check a flood zone 1,074 historic places

Health statistics

Share of adults in Middlesex County, MA, CDC PLACES estimates

All 40 measures

Obesity

23.8%

U.S. 33.3% -9.5 pts

Diabetes

8.5%

U.S. 12.1% -3.6 pts

Smoking

9.1%

U.S. 12.8% -3.7 pts

Uninsured (18-64)

4.0%

U.S. 11.1% -7.1 pts

Cities, towns and ZIP codes in Middlesex County

Population shown

Frequently asked questions

What is the largest city in Middlesex County, MA?: Cambridge is the largest city or town in Middlesex County, with about 118,796 residents.
How many ZIP codes are in Middlesex County?: Middlesex County includes 81 ZIP Code Tabulation Areas, including 01431, 01432, 01450, 01460, 01463.
What is the population of Middlesex County, MA?: About 1,638,365 people live in Middlesex County, based on American Community Survey 5-year estimates.
What counties border Middlesex County?: Middlesex County borders Worcester County, Essex County, Suffolk County, Norfolk County, Hillsborough County, NH.