San Mateo County, CA population age distributions
A complete breakdown of San Mateo 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 | 38,822 | 5.21% |
| 5 to 9 years | 39,083 | 5.25% |
| 10 to 14 years | 43,754 | 5.87% |
| 15 to 19 years | 41,188 | 5.53% |
| 20 to 24 years | 39,100 | 5.25% |
| 25 to 29 years | 49,545 | 6.65% |
| 30 to 34 years | 57,520 | 7.72% |
| 35 to 39 years | 57,008 | 7.65% |
| 40 to 44 years | 51,733 | 6.94% |
| 45 to 49 years | 50,308 | 6.75% |
| 50 to 54 years | 50,706 | 6.81% |
| 55 to 59 years | 50,448 | 6.77% |
| 60 to 64 years | 46,992 | 6.31% |
| 65 to 69 years | 40,414 | 5.42% |
| 70 to 74 years | 32,969 | 4.42% |
| 75 to 79 years | 22,251 | 2.99% |
| 80 to 84 years | 15,614 | 2.1% |
| 85 years and over | 17,645 | 2.37% |
TABLE OF CONTENTS
San Mateo County, CA population by age group
Sources: U.S. Census Bureau, American Community Survey (ACS) 2019-2023
FIGURE 1
San Mateo County, CA population by age group.
The largest age group is 30 to 34 years with a population of 57,520 (7.72% of the total population).
The largest age group in San Mateo County, CA was for the group of age 30 to 34 years with a population of 57,520 (7.72%), according to the 2019-2023 American Community Survey.
At the same time, the smallest age group in San Mateo County, CA was the 80 to 84 years with a population of 15,614 (2.10%).
San Mateo County, CA population by age cohort
To better understand the age distribution of San Mateo 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
FIGURE 2
San Mateo County, CA population by age cohort
The largest age group was 18 to 64 years with a population of 468,143 (62.83% of the total population).
San Mateo County, CA population by age cohort
Here's the population for each of the three cohorts.
| Age Group | Population | % of Total Population |
|---|---|---|
| Under 18 years | 148,064 | 19.87% |
| 18 to 64 years | 468,143 | 62.83% |
| 65 years and over | 128,893 | 17.3% |
Key stats for each age cohort as per our analysis of U.S. Census Bureau American Community Survey:
- San Mateo County 's population under 18 was 19.87%, compared to the 22.16% nationwide.
- San Mateo County's working population (between 18 and 64) was 62.83%, compared to 61% nationwide.
- San Mateo County's elderly or the senior population (over 65 age) was 17.30% as compared to 16.84% nationwide.
San Mateo County, CA population pyramid
Population pyramid for San Mateo 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 San Mateo County's population pyramid:
- Youth dependency ratio, which is the number of children aged 0-14 per 100 persons aged 15-64, for San Mateo County, CA, is 24.6.
- Old-age dependency ratio, which is the number of persons aged 65 or over per 100 persons aged 15-64, for San Mateo County, CA, is 26.1.
- Total dependency ratio for San Mateo County, CA is 50.7.
- Potential support ratio, which is the number of youth (working age population) per elderly, for San Mateo County, CA is 3.8.
FIGURE 3
San Mateo County, CA population pyramid
San Mateo County population distrubution across age and gender. A wide base suggests population increase, narrow base indicates declining birth rates.
San Mateo County, CA population pyramid
Here's the San Mateo County, CA's male and female population across different age groups .
| Age Group | Population(Male) | Population(Female) | Total Population |
|---|---|---|---|
| Under 5 years | 19,912 | 18,910 | 38,822 |
| 5 to 9 years | 20,318 | 18,765 | 39,083 |
| 10 to 14 years | 22,289 | 21,465 | 43,754 |
| 15 to 19 years | 21,245 | 19,943 | 41,188 |
| 20 to 24 years | 20,151 | 18,949 | 39,100 |
| 25 to 29 years | 25,801 | 23,744 | 49,545 |
| 30 to 34 years | 30,026 | 27,494 | 57,520 |
| 35 to 39 years | 29,467 | 27,541 | 57,008 |
| 40 to 44 years | 25,760 | 25,973 | 51,733 |
| 45 to 49 years | 25,427 | 24,881 | 50,308 |
| 50 to 54 years | 25,342 | 25,364 | 50,706 |
| 55 to 59 years | 24,792 | 25,656 | 50,448 |
| 60 to 64 years | 23,164 | 23,828 | 46,992 |
| 65 to 69 years | 19,775 | 20,639 | 40,414 |
| 70 to 74 years | 14,780 | 18,189 | 32,969 |
| 75 to 79 years | 9,562 | 12,689 | 22,251 |
| 80 to 84 years | 6,935 | 8,679 | 15,614 |
| 85 years and over | 6,468 | 11,177 | 17,645 |
Things to know
What is the population of San Mateo County, CA under 18?
San Mateo County's population under the age of 18 is 148,064, as per the latest U.S. Census Bureau's American Community Survey estimates. This population is 19.87% of the total resident population of San Mateo County, CA.
What is the aging population in San Mateo County, CA?
San Mateo County's population aged 65 years and above was 128,893. As per the U.S. Census Bureau's American Community Survey, this population is 17.30% of the entire population.
References
- U.S. Census Bureau American Community Survey (ACS) 2019-2023 5-Year Estimates