Frederick County, MD 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 267.50K Frederick County, MD population, the 35-39yrs age group constituted the highest percentage of the total population (7.52%), followed by the 50-54yrs age group (7.34%), and the 55-59yrs age group (7.24%).

In the case of age cohorts, Adults (18-64yrs) constituted the highest percentage of the total population (62.12%), followed by Children (0-17yrs) (23.39%), and Seniors (65yrs and Over) (14.49%).

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 Maryland counties, and for Maryland.

Frederick County, MD Percentages of Population By Age Group in 2021
35-39yrs
50-54yrs
55-59yrs
10-14yrs
45-49yrs
15-19yrs
30-34yrs
5-9yrs
60-64yrs
40-44yrs
Frederick County, MD Percentages of Population By Age Cohort in 2021
Adults (18-64yrs)
Children (0-17yrs)
Seniors (65yrs and Over)
Frederick County, MD Population By Age Group in 2021
0 of 0
Age Group Number of People % of Total
35-39yrs 20105 7.52
50-54yrs 19629 7.34
55-59yrs 19377 7.24
10-14yrs 18635 6.97
45-49yrs 18156 6.79
15-19yrs 18068 6.75
30-34yrs 17773 6.64
5-9yrs 17012 6.36
60-64yrs 16948 6.34
40-44yrs 16101 6.02
Under 5yrs 15666 5.86
25-29yrs 15664 5.86
20-24yrs 15613 5.84
65-69yrs 13386 5.00
70-74yrs 9930 3.71
75-79yrs 6833 2.55
85yrs and Over 4768 1.78
80-84yrs 3834 1.43
Frederick County, MD Population By Age Cohort in 2021
0 of 0
Age Cohort Number of People % of Total
Adults (18-64yrs) 166174 62.12
Children (0-17yrs) 62573 23.39
Seniors (65yrs and Over) 38751 14.49