Castle Rock Population 2026
Castle Rock has a population of 55,591, making it the #757 biggest city in 🇺🇸 United States, located in Colorado. It is about 158× smaller than New York City, the country's biggest city.
Population (city proper)
55,591
Rank in United States
#757
Coordinates
39.37°N, 104.86°W
~1,897 m elevation · America/Denver
Distance to capital (Washington)
2,391 km
1,485 miles, straight line
Other big cities in Colorado
| City | Population | Rank in United States |
|---|---|---|
| Denver | 729,019 | #19 |
| Colorado Springs | 456,568 | #43 |
| Aurora | 359,407 | #54 |
| Fort Collins | 170,924 | #156 |
| Lakewood | 152,597 | #180 |
| Thornton | 133,451 | #210 |
| Westminster | 116,317 | #253 |
| Arvada | 115,368 | #256 |
Cities near Castle Rock
- Parker49,550 people · ~18 km away
- Highlands Ranch96,713 people · ~22 km away
- Centennial109,741 people · ~23 km away
- Greenwood Village15,663 people · ~28 km away
- Littleton46,368 people · ~30 km away
- Ken Caryl32,438 people · ~32 km away
FAQ
What is the population of Castle Rock?
Castle Rock has a population of 55,591 (city proper, latest official figure via GeoNames), making it the #757 biggest city in United States.
What state is Castle Rock in?
Castle Rock is located in Colorado, United States.
Is Castle Rock the capital of United States?
No, the capital of United States is Washington D.C., about 2,391 km away.
Sources & notes
Population refers to the city proper (municipal boundaries), not the metropolitan area. Source: GeoNames (CC BY 4.0), retrieved 2026-07-07. Country data: UN World Population Prospects 2024.
← All biggest cities in United States · United States population by year