By Prerna Kapoor, CLHMS | REAL Brokerage | October 2, 2026
Castle Rock has three ZIP codes: 80104, 80108 and 80109. 80104 is the primary ZIP and includes downtown, 80108 sits on the north side of town and also accepts “Castle Pines” as a mailing city, and 80109 includes The Meadows. A ZIP code tells you where your mail goes. It doesn’t tell you which town, taxing district or HOA a house belongs to.
That last part trips up buyers all the time. If you’re still sorting out which part of Castle Rock fits you, start with my Living in Castle Rock guide. And if you’re buying here soon, my free buyer’s guide covers the steps that come after you’ve picked an address.
The Three Castle Rock Zip Codes at a Glance
According to ZipCodesToGo and Wikipedia, Castle Rock is served by 80104, 80108 and 80109, all in Douglas County. Here’s how they compare, using figures from United States Zip Codes, which draws on Census data:
80104: about 70.7 square miles of land, roughly 34,700 residents, and an estimated median home value of $586,800.
80108: about 35.3 square miles, roughly 32,200 residents, and an estimated median home value of $813,500.
80109: about 26 square miles, roughly 27,100 residents, and an estimated median home value of $648,900.
Those home values are estimates for the whole ZIP, not a price for any one street. Treat them as a rough yardstick for how differently the three areas are built, not as a forecast.
Why a ZIP Code Is Bigger Than the Town
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The Town of Castle Rock covers about 34.7 square miles, according to Wikipedia. Add up the land area of the three ZIPs and you get roughly 132 square miles. That gap tells you something simple: these ZIP codes reach well past the town limits into unincorporated Douglas County.
So a “Castle Rock” mailing address can mean you live inside the town, or it can mean you live in the county with a Castle Rock address. The same thing happens next door in Parker, which I walked through in Your Address Says Parker. Your Home Might Not Actually Be in Parker.
What 80104, 80108 and 80109 Each Tend to Include
80104 is the primary Castle Rock ZIP, and it includes the downtown core. It’s also the largest of the three by land area, which means it stretches into the more rural parts of the county as well.
80108 sits on the north side of town, and the Postal Service also accepts “Castle Pines” as a city name for it. That’s why a Castle Pines mailing address can share a ZIP with a Castle Rock one even though they’re separate municipalities.
80109 includes The Meadows, the large master-planned community, judging by the addresses of the public buildings there. I’d treat these as general patterns, not boundaries. Individual streets and newer subdivisions don’t always follow the line you’d expect, so confirm any specific address before you rely on it.
How to Check Whether a Home Is Actually in Castle Rock
Start with the USPS ZIP Code lookup to confirm the ZIP and the preferred city name for the address. Then look at the county parcel record, which shows the jurisdiction and the taxing districts, because your tax bill follows those districts and not the ZIP code. If you want the broader picture on how taxes are built, my Colorado buyer financing playbook is a good next read.
Then ask the listing agent two questions. Is the property inside town limits? Is there a metro district or HOA that adds a fee? The answers can change your monthly cost more than the ZIP code will.
Does the ZIP Code Change the Price You Should Expect?
It can, but only loosely. A tracked sample of recent sales in 80109 on Resideline shows a median sold price of $650,000 across 316 closed sales over six months, with the middle half of sales between $545,000 and $800,000. That range is wide, which is exactly the point. Two homes in the same ZIP can sit hundreds of thousands of dollars apart.
Price a home against similar homes nearby, with similar age, lot, and finish level, not against the ZIP average. If you’re also weighing the drive north, my post on south Denver suburb commute times helps you test the daily trip before you commit.
Quick Answers
How many ZIP codes does Castle Rock have?
Three: 80104, 80108 and 80109. All three are in Douglas County.
Is 80108 Castle Rock or Castle Pines?
Both. The Postal Service lists Castle Rock as the main city for 80108 and accepts Castle Pines as an alternate. Which one a specific home belongs to depends on its address and jurisdiction.
Does my ZIP code decide my property taxes?
No. Property taxes follow the taxing districts attached to the parcel, which can differ between two houses with the same ZIP. Check the county parcel record for the exact district list.
Prerna Kapoor | REALTOR® | Luxury Home Specialist
REAL Brokerage | 720-949-5450 | info@prernakapoor.com
CLHMS • RENE • PSA • ABR | International Sterling Society Award Winner
Prerna specializes in residential real estate across Parker, Aurora, Lone Tree, Castle Pines,
Highlands Ranch, Cherry Creek, Greenwood Village, and Centennial. She speaks English, Japanese,
and Hindi.
