ZIP code 80109: Castle Rock, CO

ZIP code 80109 is in Castle Rock (95% of residents), in Douglas County, Colorado. It is in Colorado's 4th congressional district. Its state senate districts are State Senate District 2 (96%) and State Senate District 4 (3.9%); its state house districts are State House District 45 (99%) and State House District 39 (0.9%).

27,148residents (2020 Census)

26.0 sq miland area

1cities and towns

1congressional district

16voting precincts

See it on the map All of Colorado

City and county

City or town	Share of ZIP residents
Castle Rock	95%

County	Share of ZIP residents
Douglas County	100%

Town or county subdivision	Share of ZIP residents
Castle Rock CCD	99%
Sedalia CCD	1.0%

Congressional district

Congressional district	Share of ZIP residents
Colorado's 4th congressional district (CO-04)	100%

Elected officials

Office	Member	Contact	Share of residents
U.S. Representative (CO-04)	Lauren Boebert (R)	202-225-4761	100%
U.S. Senator	John W. Hickenlooper (D)	202-224-5941 · contact form	statewide
U.S. Senator	Michael F. Bennet (D)	202-224-5852 · contact form	statewide
State Senator (State Senate District 2)	Lisa Frizell (R)		96%
State Senator (State Senate District 4)	Mark Baisley (R)		3.9%
State Representative (State House District 45)	Max Brooks (R)		99%
State Representative (State House District 39)	Brandi Bradley (R)		0.9%

Officials serving now (members of Congress until January 3, 2027). Sources: State legislators: Open States (public domain); Members of Congress: the @unitedstates project, congress-legislators (CC0).

Local government

Castle Rock website: http://www.townofcastlerock.org
Castle Rock laws: search for the Castle Rock, Colorado code of ordinances
Douglas County website: http://www.douglas.co.us
Douglas County laws: search for the Douglas County, Colorado code of ordinances

State legislative districts

State senate district	Share of ZIP residents
State Senate District 2	96%
State Senate District 4	3.9%

State house district	Share of ZIP residents
State House District 45	99%
State House District 39	0.9%

Voting precincts

16 voting precincts overlap ZIP 80109. Map them, with each precinct's share of the ZIP's residents.

Get this in your AI agent

Your agent can get these cities, counties, districts and precincts with their shares, and their GeoJSON boundaries, from Boundary Atlas. Add https://atlas-production-d344.up.railway.app/mcp to Claude, ChatGPT, Cursor or Codex (free, no key; how), then:

related_geographies(id="us:zcta:80109")

ZIP 80109 here is the Census Bureau's ZIP Code Tabulation Area, which approximates the USPS ZIP Code; PO-box-only ZIPs have none. Districts are the maps in force for the November 3, 2026 election.