Population of Counties in Connecticut (2020)

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. Tolland County is the second-least populated county with 150,921 people, accounting for 4.22% of the state’s population. Middlesex County is the third-smallest county with a population of 162,682, about 4.55% of the state population.

Windham, Tolland, and Middlesex County are each experiencing population declines at rate of 1.28%, 1.51%, and 1.76% respectively.

Connecticut Counties with Rapid Growth

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

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

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