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

Updated on July 8, 2024.

Based on the US Census ACS-5Yrs estimates, in 2021, among the 1.08M Montana population, the 60-64yrs age group constituted the highest percentage of the total population (7.31%), followed by the 55-59yrs age group (6.75%), and the 20-24yrs age group (6.66%).

In the case of age cohorts, Adults (18-64yrs) constituted the highest percentage of the total population (59.62%), followed by Children (0-17yrs) (21.60%), and Seniors (65yrs and Over) (18.78%).

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.

Montana Percentages of Population By Age Group in 2021
60-64yrs
55-59yrs
20-24yrs
65-69yrs
25-29yrs
35-39yrs
30-34yrs
10-14yrs
15-19yrs
5-9yrs
Montana Percentages of Population By Age Cohort in 2021
Adults (18-64yrs)
Children (0-17yrs)
Seniors (65yrs and Over)
Montana Population By Age Group in 2021
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Age Group Number of People % of Total
60-64yrs 78814 7.31
55-59yrs 72740 6.75
20-24yrs 71805 6.66
65-69yrs 71261 6.61
25-29yrs 70213 6.51
35-39yrs 69474 6.45
30-34yrs 67878 6.30
10-14yrs 67508 6.26
15-19yrs 66874 6.20
5-9yrs 64963 6.03
40-44yrs 63367 5.88
50-54yrs 61903 5.74
Under 5yrs 60366 5.60
45-49yrs 59619 5.53
70-74yrs 54207 5.03
75-79yrs 35565 3.30
80-84yrs 21039 1.95
85yrs and Over 20382 1.89
Montana Population By Age Cohort in 2021
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Age Cohort Number of People % of Total
Adults (18-64yrs) 642709 59.62
Children (0-17yrs) 232815 21.60
Seniors (65yrs and Over) 202454 18.78