Counties in Colorado by median age on 1 July (US county estimates), 2025

Custer County had the highest median age on 1 July (US county estimates) of 64 counties in 2025, at 57.5 years. Alamosa County had the lowest, at 34.4 years. The median was 42.8 years. Source: the U.S. Census Bureau.

Highest57.5Custer County

Lowest34.4Alamosa County

Median42.864 counties

Map of counties, 2025

Under 38
38 to 40
40 to 43
43 to 45
45 to 49
49 and over

years, 2025. 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.

Top 40 counties, 2025

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

Rank	Counties	2025 years	Change on 2024
1	Custer County	57.5	+0.2
2	Hinsdale County	56.9	-0.3
3	Huerfano County	56.4	-0.2
4	Mineral County	55.7	-0.2
5	Ouray County	55.5	+0.1
6	Teller County	52	0
7	Archuleta County	51.5	-0.4
7	Jackson County	51.5	+1.3
9	Costilla County	50.7	-0.3
10	Park County	50	+0.2
11	Clear Creek County	49.4	0
12	Gilpin County	49.1	+0.4
13	Sedgwick County	48.7	-0.3
14	Saguache County	48.5	-0.1
15	Delta County	48.4	+0.2
16	Las Animas County	48	+0.3
17	Chaffee County	47.9	0
18	Dolores County	47.8	-0.6
19	Montrose County	46	+0.3
20	Fremont County	45.5	+0.1
21	San Juan County	45.3	+0.1
22	Montezuma County	44.8	0
23	Rio Grande County	44.7	+0.2
24	Grand County	44.5	-0.2
25	Baca County	44.2	+0.2
26	Pitkin County	44.1	+0.2
27	La Plata County	43.8	+0.3
28	Elbert County	43.6	-0.8
28	San Miguel County	43.6	+0.6
30	Cheyenne County	43.5	+0.1
31	Routt County	43.2	+0.3
32	Kiowa County	42.8	+0.5
32	Washington County	42.8	-0.2
34	Mesa County	42.1	+0.3
35	Crowley County	41.9	+0.3
35	Otero County	41.9	+0.1
37	Bent County	41.7	+0.3
38	Pueblo County	41.1	+0.2
39	Jefferson County	40.8	+0.2
40	Rio Blanco County	40.7	+1
41	Conejos County	40.6	0
42	Eagle County	40.4	+0.4
42	Logan County	40.4	-0.2
44	Kit Carson County	40.3	-0.5
45	Phillips County	40.2	-0.1
46	Douglas County	40	+0.2
46	Moffat County	40	+0.5
48	Lincoln County	39.6	-0.4
49	Summit County	39.5	+0.5
50	Boulder County	38.8	+0.4
51	Broomfield County	38.7	+0.3
52	Larimer County	38.3	+0.2
53	Garfield County	38.2	+0.4
54	Gunnison County	37.9	-0.1
55	Yuma County	37.5	0
56	Arapahoe County	37.4	+0.3
56	Prowers County	37.4	-0.2
58	Lake County	36.8	+0.1
59	Morgan County	36.3	+0.2
60	El Paso County	35.7	+0.2
61	Weld County	35.3	+0.2
62	Adams County	35.2	+0.2
63	Denver County	35	+0.4
64	Alamosa County	34.4	+0.1

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 Colorado by median age on 1 July (US county estimates), 2025) [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 Colorado by median age on 1 July (US county estimates), 2025. 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/colorado-counties. 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 Colorado by median age on 1 July (US county estimates), 2025. 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/colorado-counties.

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 Colorado by median age on 1 July (US county estimates), 2025 [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/colorado-counties (Accessed: 12 October 2026).

BibTeX

@misc{census_counties_in_colorado_by_2025,
  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 Colorado by median age on 1 July (US county estimates), 2025}},
  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/colorado-counties. 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 Colorado by median age on 1 July (US county estimates), 2025
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/colorado-counties
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/median-age-july-1-us-counties/colorado-counties.
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)?

Custer County, with 57.5 years in 2025, according to the U.S. Census Bureau.

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

Alamosa County, with 34.4 years in 2025.

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.