County Maps US

Suffolk County, Massachusetts

A county in Massachusetts, ranked 4 of 14 by population.

CountyFIPS 25025

Within Massachusetts
Suffolk County, highlighted, with the areas around it. Boundaries generalised from the 2025 Census cartographic boundary file; neighbour fills carry no data. The dot marks Boston, the county seat, located via the 2025 Census Gazetteer.

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Population
791,891
+519 (+0.1%) since 2020
Land area
58.3
square miles. A further 51.5% of the total area is water
Population density
13,593
people per square mile, computed rather than published
County seat
Boston
Suffolk County has no county government.
Established
1643
382 years ago
Largest city
Boston city
Population 672,973.

Sources: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026; US Census Bureau, Gazetteer Files, 2025 Gazetteer Files, released 10 September 2025; Wikidata (CC0), Wikidata. Retrieved 30 August 2026.

Satellite view

Aerial imagery of Suffolk County with its boundary drawn on top. A map shows you the shape; this shows you what is inside it, and which side of the line a place falls on.

Aerial view of Suffolk County, Massachusetts from the USGS National Map, with its boundary outlined
Imagery: USGS National Map, USGS Imagery Only, public domain, requested from USGS by your browser when you reach this point on the page, at 724 by 800 pixels. The boundary is the 2025 Census cartographic boundary file, reprojected to Web Mercator to match the imagery. You can also open the USGS National Map viewer.

Where Suffolk County ranks

Position among the 14 counties of Massachusetts, and among all 3,144 US counties and county-equivalents. Computed from the figures on this page.

MeasureValueIn MassachusettsNationally
Population791,8914th of 1485th of 3,144
Land area58.3 sq mi13th of 143,101st of 3,144
Population density13,593 per sq mi1st of 147th of 3,144
Median household income$95,6318th of 14213th of 3,143

Full data for Suffolk County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population791,891Vintage 2025 Population Estimates
Population in 2020791,372Vintage 2025 Population Estimates
2020 estimates base?800,934Vintage 2025 Population Estimates
Land area58.3 sq mi2025 Gazetteer Files
Water area62.0 sq mi2025 Gazetteer Files
Total area120.2 sq mi2025 Gazetteer Files
Population density?13,593 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$95,631American Community Survey 2020-2024 5-Year Estimates
Median home value$705,800American Community Survey 2020-2024 5-Year Estimates
Median age33.9American Community Survey 2020-2024 5-Year Estimates
Households327,167American Community Survey 2020-2024 5-Year Estimates
Housing units357,290American Community Survey 2020-2024 5-Year Estimates

Sources: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026; US Census Bureau, Gazetteer Files, 2025 Gazetteer Files, released 10 September 2025; US Census Bureau, American Community Survey, American Community Survey 2020-2024 5-Year Estimates, released 29 January 2026. Population density is computed here, not published: it divides the Vintage 2025 population estimate by the 2025 Gazetteer land area, which are two different Census products. Retrieved 30 August 2026.

How the population changed

The Census Bureau publishes the components behind an estimate, not just the total. For the year to July 2025:

Births minus deaths
+3,594
8,316 births, 4,722 deaths
Net migration
-5,161
More people moved out than moved in.

Source: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026. Retrieved 30 August 2026.

The 4 areas bordering Suffolk County

Ordered by the length of the border actually shared, which the Census Bureau publishes in its county adjacency file and which no other county reference presents.

Bordering areaStateShared borderPopulation
Norfolk CountyMassachusetts33 mi739,749
Essex CountyMassachusetts25 mi826,653
Middlesex CountyMassachusetts21 mi1,669,979
Plymouth CountyMassachusetts16 mi546,829

Source: US Census Bureau, County Adjacency File, 2025 County Adjacency File, released 15 September 2025. Retrieved 30 August 2026.

Side by side

All 14 counties of Massachusetts

Open the interactive Massachusetts county map, or jump straight to any of them.

Data on this page last rebuilt 30 August 2026. How these figures are produced.