Colorado is the most populous state in the United States, with 5.2 million residents and an area of 104,094 square miles. Denver, the state’s largest city and capital, has an area of 196.32 square kilometers and a population of 649,495 at a density of 1,514 inhabitants per square kilometer, according to 2013 data. Spring is Colorado’s second-biggest city, with a population of 439,886 and the greatest area, at 504 square kilometers. Northglenn has the greatest population density at 1,878 people per square kilometer, with a total population of 37,499 and a city size of 19 square kilometers.
| Rank | Name | Population | Area (km²) | Density (inhabitants/km²) | County |
|---|---|---|---|---|---|
| 1 | Denver | 649,495 | 396.32 | 1,514 | City and County of Denver[ |
| 2 | Colorado Springs | 439,886 | 504.71 | 826 | El Paso County |
| 3 | Aurora | 345,803 | 398.49 | 814 | Arapahoe County, Adams County, Douglas County |
| 4 | Fort Collins | 152,061 | 141.46 | 1,018 | Larimer County |
| 5 | Lakewood | 147,214 | 111.04 | 1,287 | Jefferson County |
| 6 | Thornton | 127,359 | 90.79 | 1,308 | Adams County, Weld County |
| 7 | Arvada | 111,707 | 99.28 | 1,072 | Adams County, Jefferson County |
| 8 | Westminster | 110,945 | 82.04 | 1,293 | Adams County, Jefferson County |
| 9 | Pueblo | 108,249 | 138.8 | 767 | Pueblo County[ |
| 10 | Centennial | 106,114 | 74.86 | 1,341 | Arapahoe County |
| 11 | Boulder | 103,166 | 64.36 | 1,514 | Boulder County[ |
| 12 | Highlands Ranch | 102,000 | 62.83 | 1539 | Douglas County |
| 13 | Greeley | 96,539 | 122.04 | 761 | Weld County[ |
| 14 | Longmont | 89,919 | 70.59 | 1,222 | Boulder County, Weld County |
| 15 | Loveland | 71,334 | 87.67 | 762 | Larimer County |
| 16 | Grand Junction | 59,778 | 100.85 | 585 | Mesa County[ |
| 17 | Broomfield | 59,471 | 85.42 | 653 | City and County of Broomfield |
| 18 | Castle Rock | 53,063 | 87.71 | 550 | Douglas County[ |
| 19 | Commerce City | 49,799 | 90.42 | 507 | Adams County |
| 20 | Parker | 48,608 | 54.85 | 825 | Douglas County |
| 21 | Littleton | 44,275 | 32.98 | 1,265 | Arapahoe County, Jefferson County, Douglas County |
| 22 | Northglenn | 37,499 | 19.04 | 1,878 | Adams County, Weld County |
| 23 | Brighton | 35,719 | 53.05 | 636 | Adams County, Weld County |
| 24 | Englewood | 31,516 | 16.97 | 1,782 | Arapahoe County |
| 25 | Wheat Ridge | 30,920 | 24.26 | 1,244 | Jefferson County |
