Boston Metro Area Counties

7 counties · 5 million people (2025) · 3,486 sq mi

The Boston metro area (officially the Boston-Cambridge-Newton, MA-NH Metropolitan Statistical Area) has 7 counties in Massachusetts and New Hampshire, with 5,034,221 people in 2025. Middlesex County is the most populous.

Map of the 7 counties of the Boston metro area with county names and major cities
The 7 counties of the Boston metro area (yellow) with the largest cities. Boundaries: U.S. Census Bureau, 2025. Free to use with attribution (CC BY 4.0).
PDF (Letter) 321 KBPNG (2400 px) 229 KB

The 7 counties of the Boston metro area

Sorted by population. 6 are central counties (the urban core); the others are outlying counties tied to it by commuting.

CountyStateCounty seatPopulation 2025Change since 2020Land area (sq mi)Type
Middlesex CountyMassachusettsCambridge, Lowell1,669,979+2.3%818Central
Essex CountyMassachusettsSalem826,653+2.1%493Central
Suffolk CountyMassachusettsBoston791,891−1.1%58Central
Norfolk CountyMassachusettsDedham739,749+1.9%396Central
Plymouth CountyMassachusettsPlymouth546,829+3%659Central
Rockingham CountyNew HampshireBrentwood324,077+3.2%696Central
Strafford CountyNew HampshireDover135,043+3.2%368Outlying

The metro area is part of the larger Boston-Worcester-Providence, MA-RI-NH Combined Statistical Area.

Printable map

The PDF is a vector file for Letter paper; the PNG is 2400 pixels wide. Both are free to use with a credit to WhichCounty.

County maps of Massachusetts and New Hampshire

Other metro areas

Sources