Connecticut Population By Age Group and Age Cohort in 2021 (ACS-5Yrs)

Updated on February 28, 2025.

Based on the US Census ACS-5Yrs estimates, in 2021, among the 3.61M Connecticut population, the 55-59yrs age group constituted the highest percentage of the total population (7.48%), followed by the 50-54yrs age group (7.15%), and the 60-64yrs age group (6.99%).

In the case of age cohorts, Adults (18-64yrs) constituted the highest percentage of the total population (62.15%), followed by Children (0-17yrs) (20.65%), and Seniors (65yrs and Over) (17.20%).

The first and second charts below shows the percentage of the population by age group and age cohort respectively. The table below also shows the number and percentages for each age group and age cohort.

You can see similar information for other states, and the United States.

Related Topics: Connecticut ACS-5Yrs Estimates, 2021 Topic List.

Data Source: US Census - ACS 5-Year Estimates.

Connecticut Percentages of Population By Age Group in 2021

55-59yrs

50-54yrs

60-64yrs

15-19yrs

20-24yrs

45-49yrs

10-14yrs

30-34yrs

35-39yrs

25-29yrs

Connecticut Percentages of Population By Age Cohort in 2021

Adults (18-64yrs)

Children (0-17yrs)

Seniors (65yrs and Over)

Connecticut Population By Age Group in 2021

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Age Group	Number of People	% of Total
55-59yrs	269688	7.48
50-54yrs	257679	7.15
60-64yrs	252028	6.99
15-19yrs	245790	6.82
20-24yrs	241370	6.70
45-49yrs	230604	6.40
10-14yrs	224371	6.22
30-34yrs	224146	6.22
35-39yrs	223765	6.21
25-29yrs	221715	6.15
40-44yrs	215333	5.97
65-69yrs	198291	5.50
5-9yrs	196540	5.45
Under 5yrs	182122	5.05
70-74yrs	159118	4.41
75-79yrs	103370	2.87
85yrs and Over	89621	2.49
80-84yrs	69779	1.94

Connecticut Population By Age Cohort in 2021

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Age Cohort	Number of People	% of Total
Adults (18-64yrs)	2240660	62.15
Children (0-17yrs)	744491	20.65
Seniors (65yrs and Over)	620179	17.20