Ranking of Colorado Counties By Total Voting-age Population (18yrs and over) from Census 2020

Updated on February 22, 2026.

According to the data from the US 2020 Census, as at April 2020, among all the counties in Colorado, Denver County had the highest voting-age population (18 years and over) (581.06K), followed by El Paso County (558.71K), and Arapahoe County (501.68K).

The chart below shows the top 10 counties with high voting-age population, and the table below shows the ranking of all Colorado counties based on voting-age population.

You can also see the ranking of counties by population for other states as well as for the whole United States.

Ranking of Colorado Counties By Total Voting-age Population from Census 2020
Denver
El Paso
Arapahoe
Jefferson
Adams
Larimer
Boulder
Douglas
Weld
Pueblo
Ranking of Colorado Counties By Total Voting-age Population from Census 2020
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Rank County Voting-age Population
1 Denver County 581062
2 El Paso County 558711
3 Arapahoe County 501680
4 Jefferson County 469066
5 Adams County 386271
6 Larimer County 289333
7 Boulder County 268640
8 Douglas County 266006
9 Weld County 241833
10 Pueblo County 130863
11 Mesa County 123055
12 Broomfield County 57916
13 Garfield County 46166
14 La Plata County 45269
15 Eagle County 43263
16 Fremont County 41204
17 Montrose County 33608
18 Summit County 25853
19 Delta County 24993
20 Morgan County 21390
21 Teller County 20544
22 Montezuma County 20464
23 Elbert County 20395
24 Routt County 20060
25 Logan County 17431
26 Chaffee County 16471
27 Park County 14595
28 Pitkin County 14481
29 Otero County 14318
30 Gunnison County 14028
31 Grand County 13090
32 Alamosa County 12544
33 Las Animas County 12044
34 Archuleta County 10948
35 Moffat County 9993
36 Prowers County 8960
37 Rio Grande County 8959
38 Clear Creek County 8011
39 Yuma County 7320
40 San Miguel County 6515
41 Lake County 5884
42 Huerfano County 5722
43 Conejos County 5515
44 Kit Carson County 5305
45 Crowley County 5284
46 Saguache County 5096
47 Gilpin County 4916
48 Rio Blanco County 4889
49 Bent County 4745
50 Lincoln County 4485
51 Ouray County 4183
52 Custer County 3996
53 Washington County 3722
54 Phillips County 3401
55 Costilla County 2879
56 Baca County 2753
57 Dolores County 1924
58 Sedgwick County 1920
59 Cheyenne County 1338
60 Jackson County 1137
61 Kiowa County 1099
62 Mineral County 773
63 Hinsdale County 657
64 San Juan County 600