Data / Rankings / Population density / Counties in Massachusetts

Counties in Massachusetts by population density

Suffolk County had the highest population density of 14 counties in 2021, at 5,153.5 inhabitants per km². Franklin County had the lowest, at 39.2 inhabitants per km². The median was 258.6 inhabitants per km² and the figure for Massachusetts was 346.3 inhabitants per km². Source: the U.S. Census Bureau.

Highest5,153.5Suffolk County
Lowest39.2Franklin County
Median258.614 counties
Massachusetts346.3History

All counties, 2021

CSVChart (SVG)

Suffolk CountySuffolk County: 5,153.5 inhabitants per km²5,153.5Middlesex CountyMiddlesex County: 762.3 inhabitants per km²762.3Norfolk CountyNorfolk County: 706.7 inhabitants per km²706.7Essex CountyEssex County: 632.9 inhabitants per km²632.9Bristol CountyBristol County: 404.7 inhabitants per km²404.7Plymouth CountyPlymouth County: 312.4 inhabitants per km²312.4Hampden CountyHampden County: 289.5 inhabitants per km²289.5Barnstable CountyBarnstable County: 227.7 inhabitants per km²227.7Worcester CountyWorcester County: 220.4 inhabitants per km²220.4Nantucket CountyNantucket County: 121.4 inhabitants per km²121.4Hampshire CountyHampshire County: 121 inhabitants per km²121Dukes CountyDukes County: 79 inhabitants per km²79Berkshire CountyBerkshire County: 54.2 inhabitants per km²54.2Franklin CountyFranklin County: 39.2 inhabitants per km²39.2
inhabitants per km². Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-09.

Full ranking

RankCounties2021
inhabitants per km²		Change on 2020
1Suffolk County5,153.5-1.7%
2Middlesex County762.3-0.6%
3Norfolk County706.7+0.2%
4Essex County632.9-0.1%
5Bristol County404.7+0.5%
6Plymouth County312.4+0.8%
7Hampden County289.5-0.2%
8Barnstable County227.7+1.9%
9Worcester County220.4+0.6%
10Nantucket County121.4+2%
11Hampshire County121+11.2%
12Dukes County79+2.6%
13Berkshire County54.2+0.3%
14Franklin County39.2+0.2%

Other periods

About this ranking

Resident population divided by land area in km². World Bank figures use mid-year population and land area excluding inland water.

United States: Census Bureau population estimates for 1 July divided by land area (water excluded) from the latest Census Gazetteer files. US tables often give people per square mile; multiply persons per km² by 2.59 to compare.

Every value in the ranking comes from the same publisher and the same period, so the counties are compared on one definition. Equal values share a rank.

How to cite

U.S. Census Bureau. Population Estimates Program resident population on 1 July divided by land area from the latest Census Gazetteer files, persons per km². https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/. Retrieved 2026-10-09.

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Questions

Which county has the highest population density?

Suffolk County, with 5,153.5 inhabitants per km² in 2021, according to the U.S. Census Bureau.

Which county has the lowest population density?

Franklin County, with 39.2 inhabitants per km² in 2021.

Where does this ranking come from?

Every value comes from one source and one period, so the places are comparable: U.S. Census Bureau, Population Estimates Program resident population on 1 July divided by land area from the latest Census Gazetteer files, persons per km². Retrieved 2026-10-09.

Population density: other rankings

Counties in Massachusetts: more rankings