15 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Arvada | 1 | 119,461 | 124,343 | -0.81% | 3,065 | 38.97 | City |
| Dakota Ridge | 2 | 34,791 | 34,655 | 0.53% | 3,705 | 9.39 | CDP |
| Wheat Ridge | 3 | 31,420 | 32,379 | -0.61% | 3,363 | 9.34 | City |
| Golden | 4 | 20,140 | 20,394 | -0.25% | 2,091 | 9.63 | City |
| Superior | 5 | 13,531 | 13,106 | 0.63% | 3,440 | 3.93 | Town |
| Evergreen | 6 | 8,956 | 9,475 | -0.06% | 777 | 11.52 | CDP |
| Applewood | 7 | 8,191 | 8,300 | 0.85% | 2,015 | 4.07 | CDP |
| West Pleasant View | 8 | 5,536 | 5,417 | 2.08% | 3,588 | 1.54 | CDP |
| Genesee | 9 | 4,155 | 4,099 | 0.87% | 628 | 6.62 | CDP |
| Indian Hills | 10 | 1,486 | 1,363 | 0.95% | 274 | 5.42 | CDP |
| Aspen Park | 11 | 1,037 | 1,045 | 0.97% | 421 | 2.46 | CDP |
| Kittredge | 12 | 950 | 954 | -2.46% | 504 | 1.88 | CDP |
| Morrison | 13 | 381 | 398 | -0.78% | 232 | 1.65 | Town |
| Idledale | 14 | 348 | 292 | 1.75% | 1,256 | 0.28 | CDP |
| East Pleasant View | 15 | 78 | 128 | -19.59% | 703 | 0.11 | CDP |
Arvada is the largest city in Jefferson County, with a population of 119,461.
East Pleasant View is the smallest city in Jefferson County.
There are 15 cities in Jefferson County, Colorado.