ZIP code 78618: Gillespie County, TX
ZIP code 78618 is in Gillespie County (83%) and Mason County (17%), Texas, outside any city or Census-designated place. It is in Texas's 21st congressional district (83%) and Texas's 11th congressional district (17%). Its state senate districts are State Senate District 24 (83%) and State Senate District 28 (17%); its state house districts are State House District 19 (83%) and State House District 53 (17%).
City and county
Outside any city or Census-designated place.
| County | Share of ZIP residents |
|---|---|
| Gillespie County | 83% |
| Mason County | 17% |
| Town or county subdivision | Share of ZIP residents |
|---|---|
| Harper CCD | 75% |
| Mason West CCD | 17% |
| Fredericksburg CCD | 7.8% |
Congressional districts
| Congressional district | Share of ZIP residents |
|---|---|
| Texas's 21st congressional district (TX-21) | 83% |
| Texas's 11th congressional district (TX-11) | 17% |
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 |
|---|---|---|---|
| U.S. Representative (TX-21) | Chip Roy (R) | 202-225-4236 | 83% |
| U.S. Representative (TX-11) | August Pfluger (R) | 202-225-3605 | 17% |
| 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 24) | Pete Flores (R) | 830-896-9816 | 83% |
| State Senator (State Senate District 28) | Charles Perry (R) | 940-937-0909 | 17% |
| State Representative (State House District 19) | Ellen Troxclair (R) | 83% | |
| State Representative (State House District 53) | Wes Virdell (R) | 830-730-5925 | 17% |
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).
Local government
- Gillespie County website: https://www.gillespiecounty.gov/
- Gillespie County laws: search for the Gillespie County, Texas code of ordinances
- Mason County website: https://www.co.mason.tx.us/
- Mason County laws: search for the Mason County, Texas code of ordinances
State legislative districts
| State senate district | Share of ZIP residents |
|---|---|
| State Senate District 24 | 83% |
| State Senate District 28 | 17% |
| State house district | Share of ZIP residents |
|---|---|
| State House District 19 | 83% |
| State House District 53 | 17% |
Voting precincts
5 voting precincts overlap ZIP 78618. 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:78618")
ZIP 78618 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.