Massachusetts Counties by Population (2025)

There are 14 counties in Massachusetts.

The most populous county in Massachusetts is Middlesex County, with a population of 1,614,614. This represents an increase in the population of 7.1% since the 2010 census. Middlesex County is home to the city of Lowell and part of the Boston-Cambridge metro area.

Following Middlesex County are:

• Worcester County: 830,839 (City of Worcester)
• Suffolk County: 807,252 (City of Boston, growth rate of 11.22%)
• Essex County: 790,638 (Cities of Salem and Lynn)
• Norfolk County: 705,388

Massachusetts is also home to two other counties with more than 500,000 residents and four other counties with populations ranging from 100,000 to 499,999. Of the five largest counties, Suffolk County experienced the greatest population growth of 11.22% since 2010.

Massachusetts Counties with the Fewest Residents

The county that has the fewest residents in Massachusetts is Nantucket County. Since the 2010 census, Nantucket County has experienced a growth rate of 11.41%, making it the fastest-growing county in the state. Nantucket County’s population is 11,327.

Following Nantucket County as the county with the fewest residents in Massachusetts are:

• Dukes County: 17,352
• Franklin County: 70,963
• Berkshire County: 126,348 (growth rate of -3.79%)

Of these counties, Berkshire County had the most significant population loss of -3.79%.

Massachusetts Counties with Rapid Growth

Nantucket County has seen the most rapid rate of growth in Massachusetts, having grown by 11.41% since the 2010 United States census, with the population standing at 11,327.

Following Nantucket County are:

• Suffolk County: Growth rate of 11.22%
• Middlesex County: Growth rate of 7.10%
• Essex County: Growth rate of 6.06%

Berkshire County has seen the lowest rate of growth with a population growth rate of -3.79% since 2010.