Marin County, CA Population by Age

The median age in Marin County, CA is 47.1, as per 2021 ACS 5-Year Estimates. Of the total population, 16.10% were under the age of 15, 14.50% aged 15 to 29, 47.04% aged 30 to 64, 19.66% aged 65 to 84, and 2.70% were 85 years of age and older.
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Updated Sep 17, 2023

Marin County, CA population age distribution

A complete breakdown of Marin 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 11,748 4.48%
5 to 9 years 13,938 5.31%
10 to 14 years 16,548 6.31%
15 to 19 years 15,723 5.99%
20 to 24 years 11,730 4.47%
25 to 29 years 10,586 4.03%
30 to 34 years 12,068 4.6%
35 to 39 years 14,537 5.54%
40 to 44 years 16,410 6.25%
45 to 49 years 20,106 7.66%
50 to 54 years 20,469 7.8%
55 to 59 years 21,251 8.1%
60 to 64 years 18,597 7.09%
65 to 69 years 18,094 6.9%
70 to 74 years 16,099 6.14%
75 to 79 years 10,227 3.9%
80 to 84 years 7,164 2.73%
85 years and over 7,092 2.7%
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Marin County, CA population by age group

Key stats
69,687
Population under 25 years
53,601
Population aged 25-44
80,423
Population aged 45-64
58,676
Population aged 65+

Sources: U.S. Census Bureau, American Community Survey (ACS) 2021

The graph shows Marin County's population by age group, with age group on x-axis and the respective age group's percent of the total population on y-axis
Marin County, CA population by age group. The largest age group was 55-59 years with a poulation of 21,251 (8.10% of the total population). Source: U.S. Census Bureau American Community Survey (ACS) 2017-2021 5-Year Estimates.

The largest age group in Marin County, CA was for the group of age 55-59 years with a population of 21,251 (8.10%), according to the 2021 American Community Survey.

At the same time, the smallest age group in Marin County, CA was the 85+ years with a population of 7,092 (2.70%).

Marin County, CA population by age cohort

To better understand the age distribution of Marin 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
The pie chart shows Marin County's population divided into segments, with each segment representing an age cohort. The area of each segment is in the same proportion of a circle as the population of the cohort is of the total population.
Marin County, CA population by age cohorts (Children: Under 18 years; Working population: 18-64 years; Senior population: 65 years or more). The largest age group was 18 - 64 years with a poulation of 151,257 (57.65% of the total population). Source: U.S. Census Bureau American Community Survey (ACS) 2017-2021 5-Year Estimates.

Here's the population for each of the three cohorts.

Age Group Population % of Total Population
Under 18 years 52,454 19.99%
18 to 64 years 151,257 57.65%
85 years and over 58,676 22.36%
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Key stats for each age cohort as per our analysis of U.S. Census Bureau American Community Survey:

  • Marin County's population under 18 was 19.99%, compared to the 22.51% nationwide.
  • Marin County's working population (between 18 and 64) was 57.65%, compared to 61.45% nationwide.
  • Marin County's elderly or the senior population (over 65 age) was 22.36% as compared to 16.04% nationwide.

Marin County, CA population pyramid

Population pyramid for Marin 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 Marin County's population pyramid:

  • Youth dependency ratio, which is the number of children aged 0-14 per 100 persons aged 15-64, for Marin County, CA, is 26.2.
  • Old-age dependency ratio, which is the number of persons aged 65 or over per 100 persons aged 15-64, for Marin County, CA, is 36.3.
  • Total dependency ratio for Marin County, CA is 62.5.
  • Potential support ratio, which is the number of youth (working age population) per elderly, for Marin County, CA is 2.8.
The graph shows Marin County's population across different age group and gender, with population on x-axis and population y-axis. The male population is plotted on the left in blue color whereas the female population is plotted on the right in pink color.
Marin County, CA population pyramid i.e. Marin County population distrubution across age and gender. Source: U.S. Census Bureau American Community Survey (ACS) 2017-2021 5-Year Estimates.

Here's the Marin County, CA's male and female population across different age groups:

Age Group Population(Male) Population(Female) Total Population
Under 5 years 5,946 5,802 11,748
5 to 9 years 7,118 6,820 13,938
10 to 14 years 8,388 8,160 16,548
15 to 19 years 7,997 7,726 15,723
20 to 24 years 6,026 5,704 11,730
25 to 29 years 5,668 4,918 10,586
30 to 34 years 6,367 5,701 12,068
35 to 39 years 7,181 7,356 14,537
40 to 44 years 8,556 7,854 16,410
45 to 49 years 10,125 9,981 20,106
50 to 54 years 10,203 10,266 20,469
55 to 59 years 9,949 11,302 21,251
60 to 64 years 9,309 9,288 18,597
65 to 69 years 8,526 9,568 18,094
70 to 74 years 7,311 8,788 16,099
75 to 79 years 4,922 5,305 10,227
80 to 84 years 3,106 4,058 7,164
85 years and over 2,446 4,646 7,092
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Things to know

What is the population of Marin County, CA under 18?

Marin County's population under the age of 18 is 52,454, as per the latest U.S. Census Bureau's American Community Survey estimates. This population is 19.99% of the total resident population of Marin County, CA.

What is the aging population in Marin County, CA?

Marin County's population aged 65 years and above was 58,676. As per the U.S. Census Bureau's American Community Survey, this population is 22.36% of the entire population.

References

Datasets

Marin County, CA Age Group Population Dataset: A complete breakdown of Marin County age demographics from 0 to 85 years, distributed across 18 age groups
ACS
Free
Neilsberg
CSV, JSON
2017-2021
CC BY 4.0
About this dataset

Context

The dataset tabulates the Marin County population distribution across 18 age groups. It lists the population in each age group along with the percentage population relative of the total population for Marin County. The dataset can be utilized to understand the population distribution of Marin County by age. For example, using this dataset, we can identify the largest age group in Marin County.

Key observations

The largest age group in Marin County, CA was for the group of age 55-59 years with a population of 21,251 (8.10%), according to the 2021 American Community Survey. At the same time, the smallest age group in Marin County, CA was the 85+ years with a population of 7,092 (2.70%). Source: U.S. Census Bureau American Community Survey (ACS) 2017-2021 5-Year Estimates.

Marin County population by age group

Content

When available, the data consists of estimates from the U.S. Census Bureau American Community Survey (ACS) 2017-2021 5-Year Estimates.

Age groups:

  • Under 5 years
  • 5 to 9 years
  • 10 to 14 years
  • 15 to 19 years
  • 20 to 24 years
  • 25 to 29 years
  • 30 to 34 years
  • 35 to 39 years
  • 40 to 44 years
  • 45 to 49 years
  • 50 to 54 years
  • 55 to 59 years
  • 60 to 64 years
  • 65 to 69 years
  • 70 to 74 years
  • 75 to 79 years
  • 80 to 84 years
  • 85 years and over

Variables / Data Columns

  • Age Group: This column displays the age group in consideration
  • Population: The population for the specific age group in the Marin County is shown in this column.
  • % of Total Population: This column displays the population of each age group as a proportion of Marin County total population. Please note that the sum of all percentages may not equal one due to rounding of values.

Good to know

Margin of Error

Data in the dataset are based on the estimates and are subject to sampling variability and thus a margin of error. Neilsberg Research recommends using caution when presening these estimates in your research.

Custom data

If you do need custom data for any of your research project, report or presentation, you can contact our research staff at research@neilsberg.com for a feasibility of a custom tabulation on a fee-for-service basis.

Inspiration

Neilsberg Research Team curates, analyze and publishes demographics and economic data from a variety of public and proprietary sources, each of which often includes multiple surveys and programs. The large majority of Neilsberg Research aggregated datasets and insights is made available for free download at https://www.neilsberg.com/research/.

Recommended for further research

This dataset is a part of the main dataset for Marin County Population by Age. You can refer the same here

Marin County, CA Age Cohorts Dataset: Children, Working Adults, and Seniors in Marin County - Population and Percentage Analysis
ACS
Free
Neilsberg
CSV, JSON
2017-2021
CC BY 4.0
About this dataset

Context

The dataset tabulates the Marin County population by age cohorts (Children: Under 18 years; Working population: 18-64 years; Senior population: 65 years or more). It lists the population in each age cohort group along with its percentage relative to the total population of Marin County. The dataset can be utilized to understand the population distribution across children, working population and senior population for dependency ratio, housing requirements, ageing, migration patterns etc.

Key observations

The largest age group was $b3_v1 with a poulation of $b3_v2 ($b3_v3 of the total population). Source: U.S. Census Bureau American Community Survey (ACS) 2017-2021 5-Year Estimates.

Marin County population by age cohort

Content

When available, the data consists of estimates from the U.S. Census Bureau American Community Survey (ACS) 2017-2021 5-Year Estimates.

Age cohorts:

  • Under 18 years
  • 18 to 64 years
  • 65 years and over

Variables / Data Columns

  • Age Group: This column displays the age cohort for the Marin County population analysis. Total expected values are 3 groups ( Children, Working Population and Senior Population).
  • Population: The population for the age cohort in Marin County is shown in the following column.
  • Percent of Total Population: The population as a percent of total population of the Marin County is shown in the following column.

Good to know

Margin of Error

Data in the dataset are based on the estimates and are subject to sampling variability and thus a margin of error. Neilsberg Research recommends using caution when presening these estimates in your research.

Custom data

If you do need custom data for any of your research project, report or presentation, you can contact our research staff at research@neilsberg.com for a feasibility of a custom tabulation on a fee-for-service basis.

Inspiration

Neilsberg Research Team curates, analyze and publishes demographics and economic data from a variety of public and proprietary sources, each of which often includes multiple surveys and programs. The large majority of Neilsberg Research aggregated datasets and insights is made available for free download at https://www.neilsberg.com/research/.

Recommended for further research

This dataset is a part of the main dataset for Marin County Population by Age. You can refer the same here

Marin County, CA Population Pyramid Dataset: Age Groups, Male and Female Population, and Total Population for Demographics Analysis
ACS
Free
Neilsberg
CSV, JSON
2017-2021
CC BY 4.0
About this dataset

Context

The dataset tabulates the data for the Marin County, CA population pyramid, which represents the Marin County population distribution across age and gender, using estimates from the U.S. Census Bureau American Community Survey 5-Year estimates. It lists the male and female population for each age group, along with the total population for those age groups. Higher numbers at the bottom of the table suggest population growth, whereas higher numbers at the top indicate declining birth rates. Furthermore, the dataset can be utilized to understand the youth dependency ratio, old-age dependency ratio, total dependency ratio, and potential support ratio.

Key observations

  • Youth dependency ratio, which is the number of children aged 0-14 per 100 persons aged 15-64, for Marin County, CA, is 26.2.
  • Old-age dependency ratio, which is the number of persons aged 65 or over per 100 persons aged 15-64, for Marin County, CA, is 36.3.
  • Total dependency ratio for Marin County, CA is 62.5.
  • Potential support ratio, which is the number of youth (working age population) per elderly, for Marin County, CA is 2.8.

Marin County population pyramid

Content

When available, the data consists of estimates from the U.S. Census Bureau American Community Survey (ACS) 2017-2021 5-Year Estimates.

Age groups:

  • Under 5 years
  • 5 to 9 years
  • 10 to 14 years
  • 15 to 19 years
  • 20 to 24 years
  • 25 to 29 years
  • 30 to 34 years
  • 35 to 39 years
  • 40 to 44 years
  • 45 to 49 years
  • 50 to 54 years
  • 55 to 59 years
  • 60 to 64 years
  • 65 to 69 years
  • 70 to 74 years
  • 75 to 79 years
  • 80 to 84 years
  • 85 years and over

Variables / Data Columns

  • Age Group: This column displays the age group for the Marin County population analysis. Total expected values are 18 and are define above in the age groups section.
  • Population (Male): The male population in the Marin County for the selected age group is shown in the following column.
  • Population (Female): The female population in the Marin County for the selected age group is shown in the following column.
  • Total Population: The total population of the Marin County for the selected age group is shown in the following column.

Good to know

Margin of Error

Data in the dataset are based on the estimates and are subject to sampling variability and thus a margin of error. Neilsberg Research recommends using caution when presening these estimates in your research.

Custom data

If you do need custom data for any of your research project, report or presentation, you can contact our research staff at research@neilsberg.com for a feasibility of a custom tabulation on a fee-for-service basis.

Inspiration

Neilsberg Research Team curates, analyze and publishes demographics and economic data from a variety of public and proprietary sources, each of which often includes multiple surveys and programs. The large majority of Neilsberg Research aggregated datasets and insights is made available for free download at https://www.neilsberg.com/research/.

Recommended for further research

This dataset is a part of the main dataset for Marin County Population by Age. You can refer the same here

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Neilsberg Research
Neilsberg Research team are data scientists with expertise in processing, analysis and visualization of big data helping small businesses make right decisions.

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