ZIP code 78665: Round Rock, TX
ZIP code 78665 is in Round Rock (62% of residents), in Williamson County, Texas. 38% of its residents live outside city limits. It is in Texas's 31st congressional district (77%) and Texas's 17th congressional district (23%). Its state senate district is State Senate District 5; its state house districts are State House District 52 (73%) and State House District 136 (27%).
City and county
| City or town | Share of ZIP residents |
|---|---|
| Round Rock | 62% |
| County | Share of ZIP residents |
|---|---|
| Williamson County | 100% |
| Town or county subdivision | Share of ZIP residents |
|---|---|
| Round Rock-Georgetown CCD | 76% |
| Taylor CCD | 24% |
Congressional districts
| Congressional district | Share of ZIP residents |
|---|---|
| Texas's 31st congressional district (TX-31) | 77% |
| Texas's 17th congressional district (TX-17) | 23% |
This ZIP is split between districts. A mailing address in it could be in either; the map or locate_point gives the district for an exact address.
Elected officials
| Office | Member | Contact | Share of residents |
|---|---|---|---|
| Mayor | Craig Morgan | 62% | |
| U.S. Representative (TX-31) | John R. Carter (R) | 202-225-3864 | 77% |
| U.S. Representative (TX-17) | Pete Sessions (R) | 202-225-6105 | 23% |
| U.S. Senator | John Cornyn (R) | 202-224-2934 · contact form | statewide |
| U.S. Senator | Ted Cruz (R) | 202-224-5922 · contact form | statewide |
| State Senator (State Senate District 5) | Charles Schwertner (R) | 512-863-8456 | 100% |
| State Representative (State House District 52) | Caroline Harris Davila (R) | 512-255-6612 | 73% |
| State Representative (State House District 136) | John Bucy (Democratic) | 27% |
From Wikidata (community-maintained); confirm on the city's website.
Elected in 2024 under TX's previous congressional map; this district's lines changed for the 120th Congress (seated January 3, 2027).
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); Mayors: Wikidata (CC0).
Local government
- Round Rock website: http://www.roundrocktexas.gov/
- Round Rock laws: search for the Round Rock, Texas code of ordinances
- Williamson County website: https://www.wilcotx.gov/
- Williamson County laws: search for the Williamson County, Texas code of ordinances
State legislative districts
| State senate district | Share of ZIP residents |
|---|---|
| State Senate District 5 | 100% |
| State house district | Share of ZIP residents |
|---|---|
| State House District 52 | 73% |
| State House District 136 | 27% |
Voting precincts
22 voting precincts overlap ZIP 78665. 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:78665")
ZIP 78665 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.