Counties in Connecticut by population aged 18 to 64
South Central Connecticut Planning Region had the highest population aged 18 to 64 of 9 counties in 2021, at 62.2%. Northwest Hills Planning Region had the lowest, at 58.5%. The median was 61.4% and the figure for Connecticut was 61.4%. Source: the U.S. Census Bureau.
Map of counties, 2021
- Under 61
- 61 to 62
- 62 and over
All counties, 2021
Full ranking
| Rank | Counties | 2021 (%) | Change on 2020 |
|---|---|---|---|
| 1 | South Central Connecticut Planning Region | 62.2 | 0 pts |
| 2 | Greater Bridgeport Planning Region | 62 | +0.1 pts |
| 3 | Southeastern Connecticut Planning Region | 62 | -0.1 pts |
| 4 | Capitol Planning Region | 61.5 | 0 pts |
| 5 | Western Connecticut Planning Region | 61.4 | +0.1 pts |
| 6 | Northeastern Connecticut Planning Region | 61.3 | -0.1 pts |
| 7 | Lower Connecticut River Valley Planning Region | 60.6 | -0.1 pts |
| 8 | Naugatuck Valley Planning Region | 60.4 | -0.2 pts |
| 9 | Northwest Hills Planning Region | 58.5 | -0.5 pts |
Other periods
About this ranking
Residents aged 18 to 64 as a percentage of total population on 1 July. United States: Census Bureau county population estimates by age; states and the nation are sums of their counties.
Not comparable with working-age shares for ages 15 to 64 used in EU and World Bank statistics.
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. Population Estimates Program, county population by age and sex: residents aged 18 to 64 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Retrieved 2026-10-12.Citation styles
APA 7
U.S. Census Bureau. (2026). Population Estimates Program, county population by age and sex: residents aged 18 to 64 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties (Counties in Connecticut by population aged 18 to 64, 2021) [Data set]. Retrieved October 12, 2026, from https://www.census.gov/programs-surveys/popest/data/data-sets.html
MLA 9
Population Estimates Program, county population by age and sex: residents aged 18 to 64 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties, Counties in Connecticut by population aged 18 to 64, 2021. U.S. Census Bureau, 25 June 2026, https://www.census.gov/programs-surveys/popest/data/data-sets.html. Invokely, https://invokely.ai/rankings/population-18-64/connecticut-counties?period=2021. Accessed 12 Oct. 2026.
Chicago (author-date)
U.S. Census Bureau. 2026. Population Estimates Program, county population by age and sex: residents aged 18 to 64 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. Counties in Connecticut by population aged 18 to 64, 2021. Dataset. Accessed October 12, 2026. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Also distributed by Invokely, https://invokely.ai/rankings/population-18-64/connecticut-counties?period=2021.
Harvard
U.S. Census Bureau (2026) Population Estimates Program, county population by age and sex: residents aged 18 to 64 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties, Counties in Connecticut by population aged 18 to 64, 2021 [Dataset]. Available at: https://www.census.gov/programs-surveys/popest/data/data-sets.html, via Invokely: https://invokely.ai/rankings/population-18-64/connecticut-counties?period=2021 (Accessed: 12 October 2026).
BibTeX
@misc{census_counties_in_connecticut_by_2021,
author = {{U.S. Census Bureau}},
title = {{Population Estimates Program, county population by age and sex: residents aged 18 to 64 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties: Counties in Connecticut by population aged 18 to 64, 2021}},
year = {2026},
howpublished = {Data set},
url = {https://www.census.gov/programs-surveys/popest/data/data-sets.html},
urldate = {2026-10-12},
note = {Accessed via Invokely, https://invokely.ai/rankings/population-18-64/connecticut-counties?period=2021. Publisher attribution: U.S. Census Bureau. Population Estimates Program, county population by age and sex: residents aged 18 to 64 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Retrieved 2026-10-12.},
}
RIS
TY - DATA
AU - U.S. Census Bureau
TI - Population Estimates Program, county population by age and sex: residents aged 18 to 64 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties: Counties in Connecticut by population aged 18 to 64, 2021
PY - 2026
DA - 2026/06/25
PB - U.S. Census Bureau
DB - Invokely
UR - https://www.census.gov/programs-surveys/popest/data/data-sets.html
L2 - https://invokely.ai/rankings/population-18-64/connecticut-counties?period=2021
Y2 - 2026/10/12
N1 - Accessed via Invokely, https://invokely.ai/rankings/population-18-64/connecticut-counties?period=2021.
N1 - Publisher attribution: U.S. Census Bureau. Population Estimates Program, county population by age and sex: residents aged 18 to 64 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Retrieved 2026-10-12.
ER -
Use this data in your AI agent
Invokely serves this figure to AI assistants through MCP and to code through a REST API, with the source and citation attached. Ask your assistant:
Rank Counties in Connecticut by population aged 18 to 64 using official data, and cite the source.
rank_places {"indicator":"population_18_64_share","level":"province","within":"Connecticut","limit":10}
GET https://invokely.ai/api/v1/rank?indicator=population_18_64_share&level=province&within=Connecticut&limit=10Questions
Which county has the highest population aged 18 to 64?
South Central Connecticut Planning Region, with 62.2% in 2021, according to the U.S. Census Bureau.
Which county has the lowest population aged 18 to 64?
Northwest Hills Planning Region, with 58.5% 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, Population Estimates Program, county population by age and sex: residents aged 18 to 64 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. Retrieved 2026-10-12.