Connecticut Counties by Population (2025)

There are 9 counties in Connecticut.

The largest county in the state of Connecticut is Fairfield County, which has a population of 943,823 people. Fairfield County’s population comprises about 26.42% of Connecticut’s total population and has grown about 2.66% since the 2010 Census.

Hartford County is the second-most populous county in Connecticut, with a population of 892,697, and home to the state’s capital, Hartford. Hartford County is experiencing a slight population decline of 0.28%.

New Haven County is the third-most populous county with 857,620 people, but is also shrinking at a rate of 0.67%.

Connecticut Counties with the Fewest Residents

Windham County is the least populated of Connecticut’s eight counties with 117,027 people. This is about 3.28% of the state’s population.

Other small counties include:

• Tolland County: 150,921 people (4.22% of the state’s population)
• Middlesex County: 162,682 people (4.55% of the state’s population)

All three counties are experiencing population declines:

• Windham County: -1.28%
• Tolland County: -1.51%
• Middlesex County: -1.76%

Connecticut Counties with Rapid Growth

Of Connecticut’s eight counties, only Fairfield County has a positive population growth rate, growing by 2.66% since the 2010 Census.

The other seven counties have declining populations. Among them, Hartford County has the smallest rate of population decline, shrinking by 0.28% since the 2010 Census. New Haven County also has a relatively small population decline of 0.67%.

The fastest shrinking county in Connecticut is Litchfield County, whose population has declined by 4.58% since the 2010 Census.