Colorado counties quiz

The 64 counties in the quiz

They’re the 64 counties of Colorado, as counted by the US Census Bureau. The state capital, Denver, is in Denver County.

How to play

In Point mode we name a county and you tap it on the map; in Type mode one lights up and you type its name (accents don’t matter); and in Time trial you get 6 seconds per question. If you miss, we show you where it was, which way it lies and a hint drawn from the data: its size rank and its neighbors.

Each game has 10, 20 or all the questions, and at the end you can practice just the ones you missed. Your best score for each mode is saved in this browser only: neither we nor anyone else can see it, and there’s no sign-up.

The hardest ones

The smallest counties are the hardest, since they barely show on the map: Broomfield (33 sq mi), Gilpin (150 sq mi), and Denver (153 sq mi). Zoom in with the buttons or two fingers to tap them.

Tips to learn them

• The 8 counties bordering Utah trace that border on the map: Dolores, Garfield, Mesa, Moffat, Montezuma, Montrose, Rio Blanco, and San Miguel.
• El Paso is the most populous (757,040 people in 2025) and, together with Denver and Arapahoe, is home to 36% of Colorado’s people.

Playing in class

If you teach in Colorado, start with your school’s county and its neighbors and add a few each day. Otherwise, it’s a good way to get to know the state before studying it.

With the Challenge your class link, everyone gets the same questions in the same order, with no accounts or passwords, and each student sees their own score, time and streak. To practice on paper, there’s a printable worksheet of the same map with an answer key.

List of all 64 counties

1. Adams pop. 554,668
2. Alamosa pop. 16,688
3. Arapahoe pop. 673,820
4. Archuleta pop. 14,306
5. Baca pop. 3,347
6. Bent pop. 5,716
7. Boulder pop. 328,560
8. Broomfield pop. 79,174
9. Chaffee pop. 20,831
10. Cheyenne pop. 1,713
11. Clear Creek pop. 8,994
12. Conejos pop. 7,529
13. Costilla pop. 3,679
14. Crowley pop. 5,677
15. Custer pop. 5,590
16. Delta pop. 32,178
17. Denver pop. 740,613
18. Dolores pop. 2,466
19. Douglas pop. 399,396
20. Eagle pop. 54,291
21. El Paso pop. 757,040
22. Elbert pop. 30,534
23. Fremont pop. 50,039
24. Garfield pop. 63,474
25. Gilpin pop. 6,073
26. Grand pop. 16,496
27. Gunnison pop. 17,439
28. Hinsdale pop. 753
29. Huerfano pop. 7,011
30. Jackson pop. 1,211
31. Jefferson pop. 580,451
32. Kiowa pop. 1,412
33. Kit Carson pop. 7,069
34. La Plata pop. 56,898
35. Lake pop. 7,552
36. Larimer pop. 377,292
37. Las Animas pop. 14,391
38. Lincoln pop. 5,645
39. Logan pop. 20,654
40. Mesa pop. 162,845
41. Mineral pop. 910
42. Moffat pop. 13,122
43. Montezuma pop. 26,678
44. Montrose pop. 44,591
45. Morgan pop. 30,306
46. Otero pop. 17,683
47. Ouray pop. 5,265
48. Park pop. 18,314
49. Phillips pop. 4,420
50. Pitkin pop. 16,625
51. Prowers pop. 11,884
52. Pueblo pop. 169,277
53. Rio Blanco pop. 6,683
54. Rio Grande pop. 11,087
55. Routt pop. 25,329
56. Saguache pop. 6,732
57. San Juan pop. 813
58. San Miguel pop. 7,753
59. Sedgwick pop. 2,247
60. Summit pop. 31,517
61. Teller pop. 24,756
62. Washington pop. 4,732
63. Weld pop. 378,426
64. Yuma pop. 9,896