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Castle Rock population

Castle Rock, Colorado had an estimated 83,815 residents on July 1, 2025, the 452nd-largest city in the US. That is up 73.8% since the 2010 Census and up 312.8% since 2000.

Castle RockColoradoPop. 83,815
Population, July 2025
83,815+14.6% since April 2020
People per sq mile
2,41234.7 sq mi of land
Median age
36.511.4% are 65 or older
Households with kids
42.1%with anyone under 18

Population by year, 2000 to 2025

17k34k50k67k84k2000: 20,30220002001: 24,7572002: 27,74220022003: 30,6402004: 33,64020042005: 36,4162006: 39,55420062007: 42,3942008: 44,85120082009: 46,8302010: 48,23120102011: 50,0952012: 51,59220122013: 53,5062014: 55,99920142015: 58,5692016: 60,19420162017: 62,3182018: 65,00520182019: 67,7382020: 73,16220202021: 76,6592022: 80,16420222023: 81,5232024: 83,00420242025: 83,8152025
Darker bars are the April 2000, 2010 and 2020 benchmarks; the rest are July 1 estimates. Source: US Census Bureau population estimates (intercensal 2000-2010, Vintage 2020 and Vintage 2025).
YearPopulationChangeBasis
202583,815+811Estimate, July 1
202483,004+1,481Estimate, July 1
202381,523+1,359Estimate, July 1
202280,164+3,505Estimate, July 1
202176,659+3,497Estimate, July 1
202073,162+5,424April 2020 estimates base
201967,738+2,733Estimate, July 1
201865,005+2,687Estimate, July 1
201762,318+2,124Estimate, July 1
201660,194+1,625Estimate, July 1
201558,569+2,570Estimate, July 1
201455,999+2,493Estimate, July 1
201353,506+1,914Estimate, July 1
201251,592+1,497Estimate, July 1
201150,095+1,864Estimate, July 1
201048,231+1,4012010 Census (April 1)
200946,830+1,979Estimate, July 1
200844,851+2,457Estimate, July 1
200742,394+2,840Estimate, July 1
200639,554+3,138Estimate, July 1
200536,416+2,776Estimate, July 1
200433,640+3,000Estimate, July 1
200330,640+2,898Estimate, July 1
200227,742+2,985Estimate, July 1
200124,757+4,455Estimate, July 1
200020,302April 2000 estimates base

Year-to-year changes across 2010 and 2020 mix census counts with estimates, so small jumps at those years are partly method changes.

Frequently asked questions

What is the population of Castle Rock in 2025?

The Census Bureau estimates Castle Rock had 83,815 residents on July 1, 2025, making it the 452nd-largest city in the US.

Is Castle Rock growing?

Yes. Castle Rock has grown 73.8% since the 2010 Census (48,231 people), and grown 14.6% since 2020.

What was the population of Castle Rock in 2000?

About 20,302 (the Census Bureau's April 2000 estimates base). By the 2010 Census it was 48,231.

How dense is Castle Rock?

Castle Rock has about 2,412 people per square mile of land (34.7 square miles).

More about Castle Rock

See cost of living, jobs and commutes in Castle Rock, Castle Rock weather by month, or every Castle Rock ZIP code. For the biggest cities in the country, see the largest US cities.