Mendocino County, CA population age distribution
A complete breakdown of Mendocino 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 | 5,080 | 5.55% |
5 to 9 years | 6,146 | 6.71% |
10 to 14 years | 5,062 | 5.53% |
15 to 19 years | 5,375 | 5.87% |
20 to 24 years | 4,720 | 5.16% |
25 to 29 years | 4,845 | 5.29% |
30 to 34 years | 5,178 | 5.66% |
35 to 39 years | 5,443 | 5.95% |
40 to 44 years | 5,426 | 5.93% |
45 to 49 years | 5,208 | 5.69% |
50 to 54 years | 5,556 | 6.07% |
55 to 59 years | 6,666 | 7.28% |
60 to 64 years | 6,332 | 6.92% |
65 to 69 years | 6,783 | 7.41% |
70 to 74 years | 6,401 | 6.99% |
75 to 79 years | 3,329 | 3.64% |
80 to 84 years | 2,150 | 2.35% |
85 years and over | 1,834 | 2% |
TABLE OF CONTENTS
Mendocino County, CA population by age group
Sources: U.S. Census Bureau, American Community Survey (ACS) 2021

The largest age group in Mendocino County, CA was for the group of age 65-69 years with a population of 6,783 (7.41%), according to the 2021 American Community Survey.
At the same time, the smallest age group in Mendocino County, CA was the 85+ years with a population of 1,834 (2.00%).
Mendocino County, CA population by age cohort
To better understand the age distribution of Mendocino County, CA'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 | 19,587 | 21.4% |
18 to 64 years | 51,450 | 56.21% |
85 years and over | 20,497 | 22.39% |
Key stats for each age cohort as per our analysis of U.S. Census Bureau American Community Survey:
- Mendocino County's population under 18 was 21.40%, compared to the 22.51% nationwide.
- Mendocino County's working population (between 18 and 64) was 56.21%, compared to 61.45% nationwide.
- Mendocino County's elderly or the senior population (over 65 age) was 22.39% as compared to 16.04% nationwide.
Mendocino County, CA population pyramid
Population pyramid for Mendocino County, CA 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 Mendocino County's population pyramid:
- Youth dependency ratio, which is the number of children aged 0-14 per 100 persons aged 15-64, for Mendocino County, CA, is 29.8.
- Old-age dependency ratio, which is the number of persons aged 65 or over per 100 persons aged 15-64, for Mendocino County, CA, is 37.4.
- Total dependency ratio for Mendocino County, CA is 67.2.
- Potential support ratio, which is the number of youth (working age population) per elderly, for Mendocino County, CA is 2.7.

Here's the Mendocino County, CA's male and female population across different age groups:
Age Group | Population(Male) | Population(Female) | Total Population |
---|---|---|---|
Under 5 years | 2,516 | 2,564 | 5,080 |
5 to 9 years | 3,129 | 3,017 | 6,146 |
10 to 14 years | 2,596 | 2,466 | 5,062 |
15 to 19 years | 2,700 | 2,675 | 5,375 |
20 to 24 years | 2,459 | 2,261 | 4,720 |
25 to 29 years | 2,501 | 2,344 | 4,845 |
30 to 34 years | 2,636 | 2,542 | 5,178 |
35 to 39 years | 2,952 | 2,491 | 5,443 |
40 to 44 years | 2,697 | 2,729 | 5,426 |
45 to 49 years | 2,642 | 2,566 | 5,208 |
50 to 54 years | 2,778 | 2,778 | 5,556 |
55 to 59 years | 3,004 | 3,662 | 6,666 |
60 to 64 years | 3,306 | 3,026 | 6,332 |
65 to 69 years | 3,067 | 3,716 | 6,783 |
70 to 74 years | 3,320 | 3,081 | 6,401 |
75 to 79 years | 1,679 | 1,650 | 3,329 |
80 to 84 years | 898 | 1,252 | 2,150 |
85 years and over | 644 | 1,190 | 1,834 |
Things to know
What is the population of Mendocino County, CA under 18?
Mendocino County's population under the age of 18 is 19,587, as per the latest U.S. Census Bureau's American Community Survey estimates. This population is 21.40% of the total resident population of Mendocino County, CA.
What is the aging population in Mendocino County, CA?
Mendocino County's population aged 65 years and above was 20,497. As per the U.S. Census Bureau's American Community Survey, this population is 22.39% of the entire population.
References
- U.S. Census Bureau American Community Survey (ACS) 2017-2021 5-Year Estimates