Data / Rankings / Population / Counties in Connecticut

Counties in Connecticut by population

Capitol Planning Region had the highest population of 9 counties in 2021, at 971,972. Northeastern Connecticut Planning Region had the lowest, at 95,622. The median was 326,850 and the figure for Connecticut was 3.61 million. Source: the U.S. Census Bureau.

Highest971,972Capitol Planning Region
Lowest95,622Northeastern Connecticut Planning Region
Median326,8509 counties
Connecticut3,607,765History

All counties, 2021

CSVChart (SVG)

Capitol Planning RegionCapitol Planning Region: 971,972 persons971,972Western Connecticut Planning Regi…Western Connecticut Planning Region: 624,102 persons624,102South Central Connecticut Plannin…South Central Connecticut Planning Region: 569,020 persons569,020Naugatuck Valley Planning RegionNaugatuck Valley Planning Region: 452,117 persons452,117Greater Bridgeport Planning RegionGreater Bridgeport Planning Region: 326,850 persons326,850Southeastern Connecticut Planning…Southeastern Connecticut Planning Region: 279,596 persons279,596Lower Connecticut River Valley Pl…Lower Connecticut River Valley Planning Region: 175,512 persons175,512Northwest Hills Planning RegionNorthwest Hills Planning Region: 112,974 persons112,974Northeastern Connecticut Planning…Northeastern Connecticut Planning Region: 95,622 persons95,622
persons. Source: U.S. Census Bureau. Retrieved 2026-10-08.

Full ranking

RankCounties2021
persons		Change on 2020
1Capitol Planning Region971,972+0.8%
2Western Connecticut Planning Region624,102+0.9%
3South Central Connecticut Planning Region569,020+0.8%
4Naugatuck Valley Planning Region452,117+0.7%
5Greater Bridgeport Planning Region326,850+0.8%
6Southeastern Connecticut Planning Region279,596+0.4%
7Lower Connecticut River Valley Planning Region175,512+1.3%
8Northwest Hills Planning Region112,974+0.7%
9Northeastern Connecticut Planning Region95,622+0.4%

Other periods

About this ranking

Resident population. Spain and the EU: 1 January, with Spanish figures from the official municipal register (Padrón). United States: Census Bureau population estimates for 1 July. Other countries and the World: World Bank mid-year estimates, which count all residents regardless of legal status or citizenship.

For Denmark, Statistics Denmark counts the registered resident population on 1 January. Greenland and the Faroe Islands are excluded. The annual series selects the first-quarter reference date from FOLK1A. The World Bank series exists for every country, so use it (through compare) to rank countries on one basis.

Every value in the ranking comes from the same publisher and the same period, so the counties are compared on one definition. Equal values share a rank.

How to cite

U.S. Census Bureau. Annual estimates of the resident population for the United States, states and counties, 1 July (Population Estimates Program). https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/. Retrieved 2026-10-08.

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Questions

Which county has the highest population?

Capitol Planning Region, with 971,972 in 2021, according to the U.S. Census Bureau.

Which county has the lowest population?

Northeastern Connecticut Planning Region, with 95,622 in 2021.

Where does this ranking come from?

Every value comes from one source and one period, so the places are comparable: U.S. Census Bureau, Annual estimates of the resident population for the United States, states and counties, 1 July (Population Estimates Program). Retrieved 2026-10-08.

Population: other rankings

Counties in Connecticut: more rankings