Connecticut Citizen Population By County in 2020 (ACS-5Yrs)

Updated on March 28, 2026.

Based on the US Census Bureau's special tabulation from the ACS 5-year estimates, in 2020, the citizen population for Connecticut was 3,329,020 and represented 93.24% of the total Connecticut population.

Among all Connecticut counties, Fairfield had the highest citizen population (840.32K), followed by Hartford (834.97K), and New Haven (804.11K).

In terms of percentages, Windham had the highest percentage of its population being citizens (97.51%), followed by Middlesex (96.99%), and Litchfield (96.83%).

The chart and table below shows the citizen population of each county and the percentage of each county's population that were citizens.

You can see similar information for other states and by state for the United States.

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Connecticut Citizen Population By County in 2020
Connecticut Citizen Population By County in 2020
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County Citizen Population % of County Population
Fairfield 840320 88.99
Hartford 834970 93.59
New Haven 804105 93.97
New London 257035 96.32
Litchfield 175410 96.83
Middlesex 157840 96.99
Tolland 145595 96.46
Windham 113750 97.51