Data / Rankings / Population / Counties in Connecticut

Counties in Connecticut by population, 2025

Capitol Planning Region had the highest population of 9 counties in 2025, at 994,115. Northeastern Connecticut Planning Region had the lowest, at 98,096. The median was 337,697 and the figure for Connecticut was 3.69 million. Source: the U.S. Census Bureau.

Highest994,115Capitol Planning Region
Lowest98,096Northeastern Connecticut Planning Region
Median337,6979 counties
Connecticut3,688,496History

All counties, 2025

CSVChart (SVG)

Capitol Planning RegionCapitol Planning Region: 994,115 persons994,115Western Connecticut Planning Regi…Western Connecticut Planning Region: 640,482 persons640,482South Central Connecticut Plannin…South Central Connecticut Planning Region: 578,741 persons578,741Naugatuck Valley Planning RegionNaugatuck Valley Planning Region: 463,349 persons463,349Greater Bridgeport Planning RegionGreater Bridgeport Planning Region: 337,697 persons337,697Southeastern Connecticut Planning…Southeastern Connecticut Planning Region: 284,015 persons284,015Lower Connecticut River Valley Pl…Lower Connecticut River Valley Planning Region: 177,311 persons177,311Northwest Hills Planning RegionNorthwest Hills Planning Region: 114,690 persons114,690Northeastern Connecticut Planning…Northeastern Connecticut Planning Region: 98,096 persons98,096
persons. Source: U.S. Census Bureau. Retrieved 2026-10-08.

Full ranking

RankCounties2025
persons		Change on 2024
1Capitol Planning Region994,115+0.5%
2Western Connecticut Planning Region640,482+0.4%
3South Central Connecticut Planning Region578,741+0.2%
4Naugatuck Valley Planning Region463,349+0.4%
5Greater Bridgeport Planning Region337,697+0.4%
6Southeastern Connecticut Planning Region284,015+0.3%
7Lower Connecticut River Valley Planning Region177,311+0.1%
8Northwest Hills Planning Region114,690+0.4%
9Northeastern Connecticut Planning Region98,096+0.5%

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 994,115 in 2025, according to the U.S. Census Bureau.

Which county has the lowest population?

Northeastern Connecticut Planning Region, with 98,096 in 2025.

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