Data / Rankings / High school graduate or higher, population 25 and over / Counties in Connecticut

Counties in Connecticut by high school graduate or higher, population 25 and over, 2024

Lower Connecticut River Valley Planning Region had the highest high school graduate or higher, population 25 and over of 9 counties in 2024, at 95.5%. Greater Bridgeport Planning Region had the lowest, at 87.2%. The median was 92.1% and the figure for Connecticut was 91.5%. Source: the U.S. Census Bureau.

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Highest95.5Lower Connecticut River Valley Planning Region
Lowest87.2Greater Bridgeport Planning Region
Median92.19 counties
Connecticut91.5History

Map of counties, 2024

Capitol Planning Region: 91.4 %Greater Bridgeport Planning Region: 87.2 %Lower Connecticut River Valley Planning Region: 95.5 %Naugatuck Valley Planning Region: 90.5 %Northeastern Connecticut Planning Region: 92.5 %Northwest Hills Planning Region: 94.2 %South Central Connecticut Planning Region: 92.1 %Southeastern Connecticut Planning Region: 92.8 %Western Connecticut Planning Region: 91.7 %
  • Under 91
  • 91 to 92
  • 92 to 93
  • 93 and over
%, 2024. Source: Invokely calculation with data from U.S. Census Bureau. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 2024

Lower Connecticut River Valley Planning Region: 95.5 %Lower Connecticut River Valley Pl…95.5Northwest Hills Planning Region: 94.2 %Northwest Hills Planning Region94.2Southeastern Connecticut Planning Region: 92.8 %Southeastern Connecticut Planning…92.8Northeastern Connecticut Planning Region: 92.5 %Northeastern Connecticut Planning…92.5South Central Connecticut Planning Region: 92.1 %South Central Connecticut Plannin…92.1Western Connecticut Planning Region: 91.7 %Western Connecticut Planning Regi…91.7Capitol Planning Region: 91.4 %Capitol Planning Region91.4Naugatuck Valley Planning Region: 90.5 %Naugatuck Valley Planning Region90.5Greater Bridgeport Planning Region: 87.2 %Greater Bridgeport Planning Region87.2Lower Connecticut River Valley Planning Region: 95.5 %Lower Connecticut River Valley Planning Region95.5Northwest Hills Planning Region: 94.2 %Northwest Hills Planning Region94.2Southeastern Connecticut Planning Region: 92.8 %Southeastern Connecticut Planning Region92.8Northeastern Connecticut Planning Region: 92.5 %Northeastern Connecticut Planning Region92.5South Central Connecticut Planning Region: 92.1 %South Central Connecticut Planning Region92.1Western Connecticut Planning Region: 91.7 %Western Connecticut Planning Region91.7Capitol Planning Region: 91.4 %Capitol Planning Region91.4Naugatuck Valley Planning Region: 90.5 %Naugatuck Valley Planning Region90.5Greater Bridgeport Planning Region: 87.2 %Greater Bridgeport Planning Region87.2
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-12.

Full ranking

RankCounties2024 (%)Change on 2023
1Lower Connecticut River Valley Planning Region95.5+0.3 pts
2Northwest Hills Planning Region94.2+0.1 pts
3Southeastern Connecticut Planning Region92.8+0.2 pts
4Northeastern Connecticut Planning Region92.5+0.4 pts
5South Central Connecticut Planning Region92.1+0.5 pts
6Western Connecticut Planning Region91.70 pts
7Capitol Planning Region91.4+0.2 pts
8Naugatuck Valley Planning Region90.5+0.2 pts
9Greater Bridgeport Planning Region87.2-0.1 pts

Other periods

About this ranking

People aged 25 and over who hold a regular high school diploma, a GED or alternative credential, or any higher level of education, as a percentage of all people aged 25 and over. United States: American Community Survey five-year estimate, where the period shown is the last year of the five-year span.

Measures the adult population, not students: it is not the high school graduation rate of a class. Not comparable with the EU share below upper secondary education, which covers ages 25 to 64.

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. American Community Survey 5-year estimates, table B15003: population 25 years and over with a high school diploma, GED or higher as a percentage of the population 25 years and over, calculated with stored inputs. https://www2.census.gov/programs-surveys/acs/summary_file/2024/table-based-SF/data/5YRData/acsdt5y2024-b15003.dat. Retrieved 2026-10-12.

Citation styles

The publisher is the author. Invokely is named only as the place the figures were read, where a style asks for it.

APA 7

U.S. Census Bureau. (2026). American Community Survey 5-year estimates, table B15003: population 25 years and over with a high school diploma, GED or higher as a percentage of the population 25 years and over, calculated with stored inputs (Counties in Connecticut by high school graduate or higher, population 25 and over, 2024) [Data set]. Retrieved October 12, 2026, from https://www2.census.gov/programs-surveys/acs/summary_file/2024/table-based-SF/data/5YRData/acsdt5y2024-b15003.dat

MLA 9

American Community Survey 5-year estimates, table B15003: population 25 years and over with a high school diploma, GED or higher as a percentage of the population 25 years and over, calculated with stored inputs, Counties in Connecticut by high school graduate or higher, population 25 and over, 2024. U.S. Census Bureau, 29 Jan. 2026, https://www2.census.gov/programs-surveys/acs/summary_file/2024/table-based-SF/data/5YRData/acsdt5y2024-b15003.dat. Invokely, https://invokely.ai/rankings/high-school-graduate-or-higher/connecticut-counties. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Census Bureau. 2026. American Community Survey 5-year estimates, table B15003: population 25 years and over with a high school diploma, GED or higher as a percentage of the population 25 years and over, calculated with stored inputs. Counties in Connecticut by high school graduate or higher, population 25 and over, 2024. Dataset. Accessed October 12, 2026. https://www2.census.gov/programs-surveys/acs/summary_file/2024/table-based-SF/data/5YRData/acsdt5y2024-b15003.dat. Also distributed by Invokely, https://invokely.ai/rankings/high-school-graduate-or-higher/connecticut-counties.

Harvard

U.S. Census Bureau (2026) American Community Survey 5-year estimates, table B15003: population 25 years and over with a high school diploma, GED or higher as a percentage of the population 25 years and over, calculated with stored inputs, Counties in Connecticut by high school graduate or higher, population 25 and over, 2024 [Dataset]. Available at: https://www2.census.gov/programs-surveys/acs/summary_file/2024/table-based-SF/data/5YRData/acsdt5y2024-b15003.dat, via Invokely: https://invokely.ai/rankings/high-school-graduate-or-higher/connecticut-counties (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_connecticut_by_2024,
  author = {{U.S. Census Bureau}},
  title = {{American Community Survey 5-year estimates, table B15003: population 25 years and over with a high school diploma, GED or higher as a percentage of the population 25 years and over, calculated with stored inputs: Counties in Connecticut by high school graduate or higher, population 25 and over, 2024}},
  year = {2026},
  howpublished = {Data set},
  url = {https://www2.census.gov/programs-surveys/acs/summary_file/2024/table-based-SF/data/5YRData/acsdt5y2024-b15003.dat},
  urldate = {2026-10-12},
  note = {Accessed via Invokely, https://invokely.ai/rankings/high-school-graduate-or-higher/connecticut-counties. Publisher attribution: U.S. Census Bureau. American Community Survey 5-year estimates, table B15003: population 25 years and over with a high school diploma, GED or higher as a percentage of the population 25 years and over, calculated with stored inputs. https://www2.census.gov/programs-surveys/acs/summary\_file/2024/table-based-SF/data/5YRData/acsdt5y2024-b15003.dat. Retrieved 2026-10-12.},
}
RIS
TY  - DATA
AU  - U.S. Census Bureau
TI  - American Community Survey 5-year estimates, table B15003: population 25 years and over with a high school diploma, GED or higher as a percentage of the population 25 years and over, calculated with stored inputs: Counties in Connecticut by high school graduate or higher, population 25 and over, 2024
PY  - 2026
DA  - 2026/01/29
PB  - U.S. Census Bureau
DB  - Invokely
UR  - https://www2.census.gov/programs-surveys/acs/summary_file/2024/table-based-SF/data/5YRData/acsdt5y2024-b15003.dat
L2  - https://invokely.ai/rankings/high-school-graduate-or-higher/connecticut-counties
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/high-school-graduate-or-higher/connecticut-counties.
N1  - Publisher attribution: U.S. Census Bureau. American Community Survey 5-year estimates, table B15003: population 25 years and over with a high school diploma, GED or higher as a percentage of the population 25 years and over, calculated with stored inputs. https://www2.census.gov/programs-surveys/acs/summary_file/2024/table-based-SF/data/5YRData/acsdt5y2024-b15003.dat. Retrieved 2026-10-12.
ER  -
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Rank Counties in Connecticut by high school graduate or higher, population 25 and over using official data, and cite the source.
rank_places {"indicator":"high_school_graduate_share","level":"province","within":"Connecticut","limit":10}
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Questions

Which county has the highest high school graduate or higher, population 25 and over?

Lower Connecticut River Valley Planning Region, with 95.5% in 2024, according to the U.S. Census Bureau.

Which county has the lowest high school graduate or higher, population 25 and over?

Greater Bridgeport Planning Region, with 87.2% in 2024.

Where does this ranking come from?

Every value comes from one source and one period, so the places are comparable: U.S. Census Bureau, American Community Survey 5-year estimates, table B15003: population 25 years and over with a high school diploma, GED or higher as a percentage of the population 25 years and over, calculated with stored inputs. Retrieved 2026-10-12.

High school graduate or higher, population 25 and over: other rankings

Counties in Connecticut: more rankings