Data / Rankings / Population / Counties in Connecticut

Counties in Connecticut by population

Capitol Planning Region had the highest population of 9 counties in 2020, at 964,034. Northeastern Connecticut Planning Region had the lowest, at 95,212. The median was 324,360 and the figure for Connecticut was 3.58 million. Source: the U.S. Census Bureau.

Highest964,034Capitol Planning Region
Lowest95,212Northeastern Connecticut Planning Region
Median324,3609 counties
Connecticut3,579,643History

All counties, 2020

CSVChart (SVG)

Capitol Planning RegionCapitol Planning Region: 964,034 persons964,034Western Connecticut Planning Regi…Western Connecticut Planning Region: 618,740 persons618,740South Central Connecticut Plannin…South Central Connecticut Planning Region: 564,449 persons564,449Naugatuck Valley Planning RegionNaugatuck Valley Planning Region: 448,993 persons448,993Greater Bridgeport Planning RegionGreater Bridgeport Planning Region: 324,360 persons324,360Southeastern Connecticut Planning…Southeastern Connecticut Planning Region: 278,383 persons278,383Lower Connecticut River Valley Pl…Lower Connecticut River Valley Planning Region: 173,266 persons173,266Northwest Hills Planning RegionNorthwest Hills Planning Region: 112,206 persons112,206Northeastern Connecticut Planning…Northeastern Connecticut Planning Region: 95,212 persons95,212
persons. Source: U.S. Census Bureau. Retrieved 2026-10-08.

Full ranking

RankCounties2020
persons
1Capitol Planning Region964,034
2Western Connecticut Planning Region618,740
3South Central Connecticut Planning Region564,449
4Naugatuck Valley Planning Region448,993
5Greater Bridgeport Planning Region324,360
6Southeastern Connecticut Planning Region278,383
7Lower Connecticut River Valley Planning Region173,266
8Northwest Hills Planning Region112,206
9Northeastern Connecticut Planning Region95,212

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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Rank Counties in Connecticut by population using official data, and cite the source.
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Questions

Which county has the highest population?

Capitol Planning Region, with 964,034 in 2020, according to the U.S. Census Bureau.

Which county has the lowest population?

Northeastern Connecticut Planning Region, with 95,212 in 2020.

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