Data / Rankings / Median age on 1 July (US county estimates) / Counties in California

Counties in California by median age on 1 July (US county estimates)

Sierra County had the highest median age on 1 July (US county estimates) of 58 counties in 2019, at 54.4 years. Merced County had the lowest, at 31.8 years. The median was 38.8 years. Source: the U.S. Census Bureau.

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Highest54.4Sierra County
Lowest31.8Merced County
Median38.858 counties

Map of counties, 2019

Alameda County: 37.5 yearsAlpine County: 48.7 yearsAmador County: 51.5 yearsButte County: 37.9 yearsCalaveras County: 51.5 yearsColusa County: 35.2 yearsContra Costa County: 39.8 yearsDel Norte County: 40.1 yearsEl Dorado County: 46.3 yearsFresno County: 33.1 yearsGlenn County: 37.7 yearsHumboldt County: 38.9 yearsImperial County: 34.3 yearsInyo County: 45.1 yearsKern County: 32.6 yearsKings County: 32.8 yearsLake County: 45.3 yearsLassen County: 37.4 yearsLos Angeles County: 37.3 yearsMadera County: 34.8 yearsMarin County: 46.4 yearsMariposa County: 52.3 yearsMendocino County: 43.1 yearsMerced County: 31.8 yearsModoc County: 48.1 yearsMono County: 39.3 yearsMonterey County: 34.8 yearsNapa County: 42.6 yearsNevada County: 49.8 yearsOrange County: 38.8 yearsPlacer County: 42.3 yearsPlumas County: 53 yearsRiverside County: 36.6 yearsSacramento County: 36.8 yearsSan Benito County: 36.5 yearsSan Bernardino County: 34.6 yearsSan Diego County: 36.9 yearsSan Francisco County: 38 yearsSan Joaquin County: 35.2 yearsSan Luis Obispo County: 41.2 yearsSan Mateo County: 39.7 yearsSanta Barbara County: 35.5 yearsSanta Clara County: 37.3 yearsSanta Cruz County: 39.7 yearsShasta County: 42.9 yearsSierra County: 54.4 yearsSiskiyou County: 48.4 yearsSolano County: 38.8 yearsSonoma County: 42.4 yearsStanislaus County: 35.3 yearsSutter County: 36.8 yearsTehama County: 40.4 yearsTrinity County: 47.9 yearsTulare County: 32.1 yearsTuolumne County: 49 yearsVentura County: 39.2 yearsYolo County: 33 yearsYuba County: 34.2 years
  • Under 35
  • 35 to 37
  • 37 to 39
  • 39 to 42
  • 42 to 48
  • 48 and over
years, 2019. Source: U.S. Census Bureau, Population Estimates Program, county population by age and sex: median age (MEDIAN_AGE_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 2019

Sierra County: 54.4 yearsSierra County54.4Plumas County: 53 yearsPlumas County53Mariposa County: 52.3 yearsMariposa County52.3Amador County: 51.5 yearsAmador County51.5Calaveras County: 51.5 yearsCalaveras County51.5Nevada County: 49.8 yearsNevada County49.8Tuolumne County: 49 yearsTuolumne County49Alpine County: 48.7 yearsAlpine County48.7Siskiyou County: 48.4 yearsSiskiyou County48.4Modoc County: 48.1 yearsModoc County48.1Trinity County: 47.9 yearsTrinity County47.9Marin County: 46.4 yearsMarin County46.4El Dorado County: 46.3 yearsEl Dorado County46.3Lake County: 45.3 yearsLake County45.3Inyo County: 45.1 yearsInyo County45.1Mendocino County: 43.1 yearsMendocino County43.1Shasta County: 42.9 yearsShasta County42.9Napa County: 42.6 yearsNapa County42.6Sonoma County: 42.4 yearsSonoma County42.4Placer County: 42.3 yearsPlacer County42.3San Luis Obispo County: 41.2 yearsSan Luis Obispo County41.2Tehama County: 40.4 yearsTehama County40.4Del Norte County: 40.1 yearsDel Norte County40.1Contra Costa County: 39.8 yearsContra Costa County39.8San Mateo County: 39.7 yearsSan Mateo County39.7Santa Cruz County: 39.7 yearsSanta Cruz County39.7Mono County: 39.3 yearsMono County39.3Ventura County: 39.2 yearsVentura County39.2Humboldt County: 38.9 yearsHumboldt County38.9Orange County: 38.8 yearsOrange County38.8Solano County: 38.8 yearsSolano County38.8San Francisco County: 38 yearsSan Francisco County38Butte County: 37.9 yearsButte County37.9Glenn County: 37.7 yearsGlenn County37.7Alameda County: 37.5 yearsAlameda County37.5Lassen County: 37.4 yearsLassen County37.4Los Angeles County: 37.3 yearsLos Angeles County37.3Santa Clara County: 37.3 yearsSanta Clara County37.3San Diego County: 36.9 yearsSan Diego County36.9Sacramento County: 36.8 yearsSacramento County36.8Sutter County: 36.8 yearsSutter County36.8Riverside County: 36.6 yearsRiverside County36.6San Benito County: 36.5 yearsSan Benito County36.5Santa Barbara County: 35.5 yearsSanta Barbara County35.5Stanislaus County: 35.3 yearsStanislaus County35.3Colusa County: 35.2 yearsColusa County35.2San Joaquin County: 35.2 yearsSan Joaquin County35.2Madera County: 34.8 yearsMadera County34.8Monterey County: 34.8 yearsMonterey County34.8San Bernardino County: 34.6 yearsSan Bernardino County34.6Imperial County: 34.3 yearsImperial County34.3Yuba County: 34.2 yearsYuba County34.2Fresno County: 33.1 yearsFresno County33.1Yolo County: 33 yearsYolo County33Kings County: 32.8 yearsKings County32.8Kern County: 32.6 yearsKern County32.6Tulare County: 32.1 yearsTulare County32.1Merced County: 31.8 yearsMerced County31.8Sierra County: 54.4 yearsSierra County54.4Plumas County: 53 yearsPlumas County53Mariposa County: 52.3 yearsMariposa County52.3Amador County: 51.5 yearsAmador County51.5Calaveras County: 51.5 yearsCalaveras County51.5Nevada County: 49.8 yearsNevada County49.8Tuolumne County: 49 yearsTuolumne County49Alpine County: 48.7 yearsAlpine County48.7Siskiyou County: 48.4 yearsSiskiyou County48.4Modoc County: 48.1 yearsModoc County48.1Trinity County: 47.9 yearsTrinity County47.9Marin County: 46.4 yearsMarin County46.4El Dorado County: 46.3 yearsEl Dorado County46.3Lake County: 45.3 yearsLake County45.3Inyo County: 45.1 yearsInyo County45.1Mendocino County: 43.1 yearsMendocino County43.1Shasta County: 42.9 yearsShasta County42.9Napa County: 42.6 yearsNapa County42.6Sonoma County: 42.4 yearsSonoma County42.4Placer County: 42.3 yearsPlacer County42.3San Luis Obispo County: 41.2 yearsSan Luis Obispo County41.2Tehama County: 40.4 yearsTehama County40.4Del Norte County: 40.1 yearsDel Norte County40.1Contra Costa County: 39.8 yearsContra Costa County39.8San Mateo County: 39.7 yearsSan Mateo County39.7Santa Cruz County: 39.7 yearsSanta Cruz County39.7Mono County: 39.3 yearsMono County39.3Ventura County: 39.2 yearsVentura County39.2Humboldt County: 38.9 yearsHumboldt County38.9Orange County: 38.8 yearsOrange County38.8Solano County: 38.8 yearsSolano County38.8San Francisco County: 38 yearsSan Francisco County38Butte County: 37.9 yearsButte County37.9Glenn County: 37.7 yearsGlenn County37.7Alameda County: 37.5 yearsAlameda County37.5Lassen County: 37.4 yearsLassen County37.4Los Angeles County: 37.3 yearsLos Angeles County37.3Santa Clara County: 37.3 yearsSanta Clara County37.3San Diego County: 36.9 yearsSan Diego County36.9Sacramento County: 36.8 yearsSacramento County36.8Sutter County: 36.8 yearsSutter County36.8Riverside County: 36.6 yearsRiverside County36.6San Benito County: 36.5 yearsSan Benito County36.5Santa Barbara County: 35.5 yearsSanta Barbara County35.5Stanislaus County: 35.3 yearsStanislaus County35.3Colusa County: 35.2 yearsColusa County35.2San Joaquin County: 35.2 yearsSan Joaquin County35.2Madera County: 34.8 yearsMadera County34.8Monterey County: 34.8 yearsMonterey County34.8San Bernardino County: 34.6 yearsSan Bernardino County34.6Imperial County: 34.3 yearsImperial County34.3Yuba County: 34.2 yearsYuba County34.2Fresno County: 33.1 yearsFresno County33.1Yolo County: 33 yearsYolo County33Kings County: 32.8 yearsKings County32.8Kern County: 32.6 yearsKern County32.6Tulare County: 32.1 yearsTulare County32.1Merced County: 31.8 yearsMerced County31.8
years. Source: U.S. Census Bureau, Population Estimates Program, county population by age and sex: median age (MEDIAN_AGE_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage. Retrieved 2026-10-12.

Full ranking

RankCounties2019
years		Change on 2018
1Sierra County54.4-0.1
2Plumas County53+0.1
3Mariposa County52.3+0.2
4Amador County51.5+0.2
4Calaveras County51.5-0.1
6Nevada County49.8+0.1
7Tuolumne County49+0.1
8Alpine County48.7-2.8
9Siskiyou County48.4+0.3
10Modoc County48.1-0.5
11Trinity County47.9-0.6
12Marin County46.4+0.2
13El Dorado County46.3+0.1
14Lake County45.3-0.3
15Inyo County45.1-0.3
16Mendocino County43.1+0.2
17Shasta County42.9-0.1
18Napa County42.6+0.4
19Sonoma County42.4+0.3
20Placer County42.3+0.2
21San Luis Obispo County41.2+0.4
22Tehama County40.4-0.1
23Del Norte County40.1+0.3
24Contra Costa County39.8+0.2
25San Mateo County39.7+0.1
25Santa Cruz County39.7+0.4
27Mono County39.3+0.2
28Ventura County39.2+0.4
29Humboldt County38.9+0.4
30Orange County38.8+0.4
30Solano County38.8+0.3
32San Francisco County380
33Butte County37.9-0.3
34Glenn County37.7+0.3
35Alameda County37.5+0.1
36Lassen County37.40
37Los Angeles County37.3+0.3
37Santa Clara County37.3+0.2
39San Diego County36.9+0.4
40Sacramento County36.8+0.3
40Sutter County36.8+0.3
42Riverside County36.6+0.4
43San Benito County36.5+0.2
44Santa Barbara County35.5+0.3
45Stanislaus County35.3+0.3
46Colusa County35.2+0.2
46San Joaquin County35.2+0.3
48Madera County34.8+0.3
48Monterey County34.8+0.2
50San Bernardino County34.6+0.4
51Imperial County34.3+0.4
52Yuba County34.2+0.3
53Fresno County33.1+0.3
54Yolo County33+0.4
55Kings County32.8+0.3
56Kern County32.6+0.2
57Tulare County32.1+0.3
58Merced County31.8+0.2

Other periods

About this ranking

Age that divides the resident population of a US county into two halves of equal size on 1 July, from Census Bureau population estimates calculated by single year of age.

Counties only: the county file has no state or national medians, and medians cannot be added up. A single-year estimate, unlike median_age, which for US places is a five-year American Community Survey estimate.

Every value in the ranking comes from the same publisher and the same period, so the counties are compared on one definition. Equal values share a rank.

How to cite

U.S. Census Bureau. Population Estimates Program, county population by age and sex: median age (MEDIAN_AGE_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Retrieved 2026-10-12.

Citation styles

The publisher is the author. Invokely is named only as the place the figures were read, where a style asks for it.

APA 7

U.S. Census Bureau. (2026). Population Estimates Program, county population by age and sex: median age (MEDIAN_AGE_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage (Counties in California by median age on 1 July (US county estimates), 2019) [Data set]. Retrieved October 12, 2026, from https://www.census.gov/programs-surveys/popest/data/data-sets.html

MLA 9

Population Estimates Program, county population by age and sex: median age (MEDIAN_AGE_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage, Counties in California by median age on 1 July (US county estimates), 2019. U.S. Census Bureau, 25 June 2026, https://www.census.gov/programs-surveys/popest/data/data-sets.html. Invokely, https://invokely.ai/rankings/median-age-july-1-us-counties/california-counties?period=2019. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Census Bureau. 2026. Population Estimates Program, county population by age and sex: median age (MEDIAN_AGE_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage. Counties in California by median age on 1 July (US county estimates), 2019. Dataset. Accessed October 12, 2026. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Also distributed by Invokely, https://invokely.ai/rankings/median-age-july-1-us-counties/california-counties?period=2019.

Harvard

U.S. Census Bureau (2026) Population Estimates Program, county population by age and sex: median age (MEDIAN_AGE_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage, Counties in California by median age on 1 July (US county estimates), 2019 [Dataset]. Available at: https://www.census.gov/programs-surveys/popest/data/data-sets.html, via Invokely: https://invokely.ai/rankings/median-age-july-1-us-counties/california-counties?period=2019 (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_california_by_2019,
  author = {{U.S. Census Bureau}},
  title = {{Population Estimates Program, county population by age and sex: median age (MEDIAN\_AGE\_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage: Counties in California by median age on 1 July (US county estimates), 2019}},
  year = {2026},
  howpublished = {Data set},
  url = {https://www.census.gov/programs-surveys/popest/data/data-sets.html},
  urldate = {2026-10-12},
  note = {Accessed via Invokely, https://invokely.ai/rankings/median-age-july-1-us-counties/california-counties?period=2019. Publisher attribution: U.S. Census Bureau. Population Estimates Program, county population by age and sex: median age (MEDIAN\_AGE\_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Retrieved 2026-10-12.},
}
RIS
TY  - DATA
AU  - U.S. Census Bureau
TI  - Population Estimates Program, county population by age and sex: median age (MEDIAN_AGE_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage: Counties in California by median age on 1 July (US county estimates), 2019
PY  - 2026
DA  - 2026/06/25
PB  - U.S. Census Bureau
DB  - Invokely
UR  - https://www.census.gov/programs-surveys/popest/data/data-sets.html
L2  - https://invokely.ai/rankings/median-age-july-1-us-counties/california-counties?period=2019
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/median-age-july-1-us-counties/california-counties?period=2019.
N1  - Publisher attribution: U.S. Census Bureau. Population Estimates Program, county population by age and sex: median age (MEDIAN_AGE_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Retrieved 2026-10-12.
ER  -
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Questions

Which county has the highest median age on 1 July (US county estimates)?

Sierra County, with 54.4 years in 2019, according to the U.S. Census Bureau.

Which county has the lowest median age on 1 July (US county estimates)?

Merced County, with 31.8 years in 2019.

Where does this ranking come from?

Every value comes from one source and one period, so the places are comparable: U.S. Census Bureau, Population Estimates Program, county population by age and sex: median age (MEDIAN_AGE_TOT) on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage. Retrieved 2026-10-12.

Median age on 1 July (US county estimates): other rankings

Counties in California: more rankings