Connecticut Population By County in 2020
Updated on June 16, 2025.
Based on the US Census Vintage data estimates, in 2020, the population of Connecticut was 3,579,918. Among all Connecticut counties, Capitol Planning Region had the highest population (964,088), followed by Western Connecticut Planning Region (618,762), and South Central Connecticut Planning Region (564,526). Northeastern Connecticut Planning Region was the least populated county (95,231).
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.
Related Topics: Connecticut Census Vintage Data Topic List.
Data Source: US Census Bureau (Vintage).
See this for other years:
Connecticut Population By County in 2020
Connecticut Population By County in 2020
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| County | Population | % of State Population |
|---|---|---|
| Capitol Planning Region | 964088 | 26.93 |
| Greater Bridgeport Planning Region | 324397 | 9.06 |
| Lower Connecticut River Valley Planning Region | 173281 | 4.84 |
| Naugatuck Valley Planning Region | 449055 | 12.54 |
| Northeastern Connecticut Planning Region | 95231 | 2.66 |
| Northwest Hills Planning Region | 112199 | 3.13 |
| South Central Connecticut Planning Region | 564526 | 15.77 |
| Southeastern Connecticut Planning Region | 278379 | 7.78 |
| Western Connecticut Planning Region | 618762 | 17.28 |