Castle Rock, Colorado: Population, Growth, and What’s Driving It Now

Where Castle Rock Sits

Castle Rock sits in the East Plum Creek Valley on the western edge of the Great Plains, a few miles east of the Rampart Range foothills, roughly midway between Denver and Colorado Springs on I-25, at an elevation near 6,200 feet and across 34.29 square miles of incorporated land. Most residents commute out of town for work: the mean travel time to work is 28.6 minutes, longer than the national average, reflecting a jobs base still concentrated in Denver and its southern suburbs. Census Bureau QuickFacts

Is Castle Rock a city or a town?A town. Colorado’s municipal classifications depend on incorporation type, not population, so Castle Rock remains legally a “town” even though it outranks most Colorado cities in size.

Population: From 48,000 to Nearly 84,000 in Fifteen Years

The Census-certified population more than tripled between 2010 and 2025.

Source: Census Bureau QuickFacts. Land area grew by less than 2% across those fifteen years while population grew by nearly 74%, the arithmetic behind the town’s ongoing debate over downtown building heights and road capacity.

Anyone who compares Castle Rock population figures across different websites will find numbers ranging from about 79,000 to nearly 88,000 for essentially the same period, and the spread comes from vintage and methodology, not a real disagreement about the town. The Census Bureau’s own July 2025 estimate is 83,815. Separately, private demographic vendors publish 2026 projections built on proprietary growth models, with one putting the figure at 87,875 and another citing 79,123 as current while actually drawing on an older vintage. World Population Review None of these projections is Census-traceable for the year they claim to describe, so the Census estimate above is the number to anchor on; a projection can still be useful for planning, but it isn’t the same kind of fact as a measured count.

How fast is Castle Rock growing?About 2 to 3% a year over the past five years, based on the Census Bureau’s own estimates, not the higher rates some private projections imply.

The Brickyard and What’s Driving Castle Rock’s Growth Now

On Oct. 7, 2025, the Town Council approved the site development plan for the Brickyard, a 21.14-acre mixed-use project at 401 Prairie Hawk Drive, on land that had sat zoned for general industrial use since 1974. The approved plan includes 384 multifamily units, a 123-room hotel with conference space, about 263,000 square feet of retail, office, restaurant, and entertainment space, and 5.49 acres of open space. Town of Castle Rock, Oct. 7 Council update The first phase, a 145,000-square-foot Castle Rock Sports Center with basketball, volleyball, and pickleball courts and a competitive pool, is under construction and expected to open in 2027. Castle Pines Connection

The town commissioned a $200,000 public art piece for the site from DKLA Design, funded through the Public Art Fund with a 5% contingency, timed for completion in summer 2026 alongside the town’s sesquisemiquincentennial events.

Growth here isn’t happening at the expense of open land: in 2024 the town partnered with Douglas County and The Conservation Fund to acquire the 681-acre Lost Canyon Ranch, the largest open-space purchase in the town’s history, which now links with Castlewood Canyon State Park to form 4,300 contiguous acres of protected habitat.

What is the Brickyard?A 384-unit, hotel-anchored mixed-use development on a former industrial site west of I-25, with its recreation center scheduled to open in 2027.

Income, Housing, and a Property-Tax Surprise

Castle Rock’s median household income was $145,197 and its median home value was $652,900 in the 2020–2024 American Community Survey. Census Bureau QuickFacts

Sources: Census Bureau QuickFacts; USAFacts; Data USA. The state figures come from a different Census series and year than the town’s five-year estimate, so treat the comparison as directional, not exact. Even accounting for that gap, the direction is consistent across every recent vintage: incomes here run well above the state, and home values track close behind them rather than pulling ahead.

At the median, a mortgaged household pays $2,787 a month, or about $33,444 a year, against the $145,197 median household income: roughly 23% of income. That sits comfortably under the 30% share HUD has used since 1981 as the line for “cost burdened,” a threshold most high-growth Front Range suburbs cross. Home prices here are high in absolute terms, but local incomes have kept the mortgage-to-income ratio below the level that typically signals a housing squeeze.

The property-tax bill doesn’t move with home values the way people expect, either. The 2026 municipal mill levy is 0.92 mills, down 45% since 2011, and the owner of the median-valued Castle Rock home ($635,119 in 2025) paid $39.15 in town property tax for the year. The town’s proposed $349.6 million 2026 budget runs mainly on sales tax, including a 0.2% increase voters approved in 2024, not on property tax revenue.

Is Castle Rock affordable to live in?By the standard federal cost-burden measure, yes for a median-income household: the typical mortgage payment runs about 23% of median income, under the 30% threshold HUD treats as cost-burdened.

Schools in Castle Rock

Castle Rock sits within Douglas County School District RE-1, Colorado’s third-largest district, which operates both comprehensive high schools and middle schools with Castle Rock addresses.

Source: U.S. News; NCES school locator; Douglas County School District. Two comprehensive high schools inside one town, alongside dozens of elementary and middle schools the district also operates, reflects how much recent housing growth the district has had to absorb.

What school district serves Castle Rock?Douglas County School District RE-1, headquartered in Castle Rock, which is Colorado’s third-largest district.

A Short History: From Frankstown’s Loss to a Rhyolite Town

In 1874, Douglas County voters moved the county seat from Frankstown to a new settlement at the base of a castle-shaped butte. Settler Jeremiah Gould, who held land south of the butte, donated 120 acres that year “to be known as Castle Rock.” Prospectors first came for rumored gold; what they found instead was rhyolite, a volcanic building stone quarried locally for decades and still visible in the town’s oldest structures. Town of Castle Rock, Town History

Why is the town named Castle Rock?For the castle-shaped butte that overlooks the town center, the same rhyolite formation that gave the local quarrying industry its name.