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

Custer County had the highest median age on 1 July (US county estimates) of 64 counties in 2020, at 58.4 years. Denver County had the lowest, at 34.1 years. The median was 41.8 years. Source: the U.S. Census Bureau.

Highest58.4Custer County

Lowest34.1Denver County

Median41.864 counties

Map of counties, 2020

Under 38
38 to 40
40 to 42
42 to 45
45 to 49
49 and over

years, 2020. 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, 2020

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	2020 years	Change on 2019
1	Custer County	58.4	+0.2
2	Mineral County	57.5	+2.1
3	Hinsdale County	56.6	+1.2
4	Huerfano County	56.4	+0.2
5	Ouray County	54.7	+0.8
6	Archuleta County	52	+0.3
7	Costilla County	51.9	+0.5
8	Teller County	51.5	+0.2
9	Sedgwick County	50	+0.5
10	Park County	49.7	+0.4
11	Chaffee County	49.3	+0.2
12	Delta County	49.1	+0.4
12	Dolores County	49.1	+0.3
14	Jackson County	48.8	-0.2
15	Las Animas County	48.5	+0.7
16	Clear Creek County	48.3	-0.2
17	Gilpin County	47.7	+0.3
18	Saguache County	47.4	+0.7
19	Fremont County	46.1	+0.2
20	Elbert County	46	0
21	Baca County	45.7	+0.2
22	Montezuma County	45.4	+0.3
22	Montrose County	45.4	+0.3
24	San Juan County	45.2	-1.6
25	Kiowa County	44.8	+2.2
26	Grand County	44.2	+0.5
27	Rio Grande County	43.7	+0.5
28	Cheyenne County	43.5	-0.2
29	Pitkin County	43.1	-0.3
30	Washington County	43	-0.1
31	Bent County	42.1	+0.8
32	Crowley County	41.8	+0.8
32	La Plata County	41.8	+0.4
32	Routt County	41.8	+0.5
35	Conejos County	41.2	+0.2
35	Otero County	41.2	+0.2
35	San Miguel County	41.2	+0.4
38	Phillips County	41.1	-0.4
39	Mesa County	40.7	+0.2
39	Pueblo County	40.7	0
41	Jefferson County	40.3	0
42	Kit Carson County	40.1	-0.2
43	Logan County	39.7	+0.4
44	Lincoln County	39.3	+0.4
45	Douglas County	39.1	+0.1
46	Moffat County	38.6	+0.5
47	Rio Blanco County	38.5	-0.2
48	Summit County	38	+0.1
49	Eagle County	37.9	+0.5
49	Prowers County	37.9	-0.1
51	Broomfield County	37.8	0
52	Yuma County	37.7	-0.5
53	Boulder County	37.6	+0.3
54	Larimer County	37.4	+0.3
55	Gunnison County	37.3	+0.2
56	Garfield County	36.8	0
57	Arapahoe County	36.6	+0.1
57	Morgan County	36.6	+0.1
59	Lake County	36.1	+0.3
60	El Paso County	35	+0.1
61	Weld County	34.5	+0.2
62	Adams County	34.4	+0.2
63	Alamosa County	34.3	-0.4
64	Denver County	34.1	0

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), 2020) [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), 2020. 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?period=2020. 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), 2020. 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?period=2020.

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), 2020 [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?period=2020 (Accessed: 12 October 2026).

BibTeX

@misc{census_counties_in_colorado_by_2020,
  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), 2020}},
  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?period=2020. 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), 2020
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?period=2020
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/median-age-july-1-us-counties/colorado-counties?period=2020.
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 58.4 years in 2020, according to the U.S. Census Bureau.

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

Denver County, with 34.1 years in 2020.

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.