Connecticut Citizen Population By County in 2015 (ACS-5Yrs)

Updated on March 28, 2026.

Based on the US Census Bureau's special tabulation from the ACS 5-year estimates, in 2015, the citizen population for Connecticut was 3,336,145 and represented 92.85% of the total Connecticut population.

Among all Connecticut counties, Hartford had the highest citizen population (832.74K), followed by Fairfield (829.97K), and New Haven (808.76K).

In terms of percentages, Windham had the highest percentage of its population being citizens (97.22%), followed by Litchfield (96.75%), and Tolland (96.70%).

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 2015
Connecticut Citizen Population By County in 2015
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County Citizen Population % of County Population
Hartford 832740 92.84
Fairfield 829970 88.30
New Haven 808755 93.80
New London 263655 96.51
Litchfield 180250 96.75
Middlesex 159635 96.65
Tolland 146935 96.70
Windham 114205 97.22