Connecticut Population By County in 2018

Updated on June 16, 2025.

Based on the US Census Vintage data estimates, in 2018, the population of Connecticut was 3,574,561. Among all Connecticut counties, Fairfield had the highest population (945,511), followed by Hartford (892,767), and New Haven (856,895). Windham was the least populated county (117,182).

Hover over or click on the counties in the map below to see the populations. The data can also be found in a table below. You can use the table to sort, filter, and explore the data further.

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

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Connecticut Population By County in 2018
Connecticut Population By County in 2018
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County Population % of State Population
Fairfield 945511 26.45
Hartford 892767 24.98
Litchfield 181151 5.07
Middlesex 163053 4.56
New Haven 856895 23.97
New London 267089 7.47
Tolland 150913 4.22
Windham 117182 3.28