Linn County, IA population age distribution
A complete breakdown of Linn County's age demographics from 0 to 85 years, distributed across 18 age groups is listed in the table below.
Age Group | Population | % of Total Population |
---|---|---|
Under 5 years | 14,086 | 6.16% |
5 to 9 years | 14,040 | 6.14% |
10 to 14 years | 15,872 | 6.94% |
15 to 19 years | 15,083 | 6.6% |
20 to 24 years | 14,774 | 6.46% |
25 to 29 years | 15,594 | 6.82% |
30 to 34 years | 15,124 | 6.62% |
35 to 39 years | 15,752 | 6.89% |
40 to 44 years | 14,419 | 6.31% |
45 to 49 years | 14,007 | 6.13% |
50 to 54 years | 14,388 | 6.29% |
55 to 59 years | 15,302 | 6.69% |
60 to 64 years | 13,762 | 6.02% |
65 to 69 years | 12,579 | 5.5% |
70 to 74 years | 8,751 | 3.83% |
75 to 79 years | 5,994 | 2.62% |
80 to 84 years | 4,131 | 1.81% |
85 years and over | 4,909 | 2.15% |
TABLE OF CONTENTS
Linn County, IA population by age group
Sources: U.S. Census Bureau, American Community Survey (ACS) 2021

The largest age group in Linn County, IA was for the group of age 10-14 years with a population of 15,872 (6.94%), according to the 2021 American Community Survey.
At the same time, the smallest age group in Linn County, IA was the 80-84 years with a population of 4,131 (1.81%).
Linn County, IA population by age cohort
To better understand the age distribution of Linn County, IA's population, we divided it into the following 3 cohorts:
- Children : Under the age of 18 years
- Adults (working population): Between the age of 18 and 64 years
- Seniors: 65 years and above

Here's the population for each of the three cohorts.
Age Group | Population | % of Total Population |
---|---|---|
Under 18 years | 53,295 | 23.32% |
18 to 64 years | 138,908 | 60.77% |
85 years and over | 36,364 | 15.91% |
Key stats for each age cohort as per our analysis of U.S. Census Bureau American Community Survey:
- Linn County's population under 18 was 23.32%, compared to the 22.51% nationwide.
- Linn County's working population (between 18 and 64) was 60.77%, compared to 61.45% nationwide.
- Linn County's elderly or the senior population (over 65 age) was 15.91% as compared to 16.04% nationwide.
Linn County, IA population pyramid
Population pyramid for Linn County, IA is charted below using the estimates from U.S. Census Bureau's American Community Survey 5-Year estimates. A wide base suggests population increase, narrow base indicates declining birth rates.
Key stats from our analysis of the Linn County's population pyramid:
- Youth dependency ratio, which is the number of children aged 0-14 per 100 persons aged 15-64, for Linn County, IA, is 29.7.
- Old-age dependency ratio, which is the number of persons aged 65 or over per 100 persons aged 15-64, for Linn County, IA, is 24.5.
- Total dependency ratio for Linn County, IA is 54.2.
- Potential support ratio, which is the number of youth (working age population) per elderly, for Linn County, IA is 4.1.

Here's the Linn County, IA's male and female population across different age groups:
Age Group | Population(Male) | Population(Female) | Total Population |
---|---|---|---|
Under 5 years | 7,076 | 7,010 | 14,086 |
5 to 9 years | 7,031 | 7,009 | 14,040 |
10 to 14 years | 8,303 | 7,569 | 15,872 |
15 to 19 years | 7,664 | 7,419 | 15,083 |
20 to 24 years | 7,355 | 7,419 | 14,774 |
25 to 29 years | 7,879 | 7,715 | 15,594 |
30 to 34 years | 7,533 | 7,591 | 15,124 |
35 to 39 years | 8,095 | 7,657 | 15,752 |
40 to 44 years | 7,226 | 7,193 | 14,419 |
45 to 49 years | 7,017 | 6,990 | 14,007 |
50 to 54 years | 7,314 | 7,074 | 14,388 |
55 to 59 years | 7,714 | 7,588 | 15,302 |
60 to 64 years | 6,635 | 7,127 | 13,762 |
65 to 69 years | 6,003 | 6,576 | 12,579 |
70 to 74 years | 4,145 | 4,606 | 8,751 |
75 to 79 years | 2,361 | 3,633 | 5,994 |
80 to 84 years | 1,805 | 2,326 | 4,131 |
85 years and over | 1,964 | 2,945 | 4,909 |
Things to know
What is the population of Linn County, IA under 18?
Linn County's population under the age of 18 is 53,295, as per the latest U.S. Census Bureau's American Community Survey estimates. This population is 23.32% of the total resident population of Linn County, IA.
What is the aging population in Linn County, IA?
Linn County's population aged 65 years and above was 36,364. As per the U.S. Census Bureau's American Community Survey, this population is 15.91% of the entire population.
References
- U.S. Census Bureau American Community Survey (ACS) 2017-2021 5-Year Estimates