ZIP code 78663: Blanco County, TX
ZIP code 78663 is in Round Mountain (12% of residents), in Blanco County (86%), Travis County (7.2%), Hays County (4.9%) and Burnet County (1.8%), Texas. 88% of its residents live outside city limits. It is in Texas's 21st congressional district (91%), Texas's 10th congressional district (7.2%) and Texas's 11th congressional district (1.8%). Its state senate districts are State Senate District 25 (98%) and State Senate District 24 (1.8%); its state house districts are State House District 19 (95%) and State House District 73 (4.9%).
City and county
| City or town | Share of ZIP residents |
|---|---|
| Round Mountain | 12% |
| County | Share of ZIP residents |
|---|---|
| Blanco County | 86% |
| Travis County | 7.2% |
| Hays County | 4.9% |
| Burnet County | 1.8% |
| Town or county subdivision | Share of ZIP residents |
|---|---|
| Johnson City CCD | 86% |
| Southwest Travis CCD | 7.2% |
| Dripping Springs-Wimberley CCD | 4.9% |
| Marble Falls CCD | 1.8% |
Congressional districts
| Congressional district | Share of ZIP residents |
|---|---|
| Texas's 21st congressional district (TX-21) | 91% |
| Texas's 10th congressional district (TX-10) | 7.2% |
| Texas's 11th congressional district (TX-11) | 1.8% |
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 | 91% |
| U.S. Representative (TX-10) | Michael T. McCaul (R) | 202-225-2401 | 7.2% |
| U.S. Representative (TX-11) | August Pfluger (R) | 202-225-3605 | 1.8% |
| 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 25) | Donna Campbell (R) | 830-626-0065 | 98% |
| State Senator (State Senate District 24) | Pete Flores (R) | 830-896-9816 | 1.8% |
| State Representative (State House District 19) | Ellen Troxclair (R) | 95% | |
| State Representative (State House District 73) | Carrie Isaac (R) | 830-730-6248 | 4.9% |
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
- Round Mountain laws: search for the Round Mountain, Texas code of ordinances
- Blanco County website: https://www.co.blanco.tx.us/
- Blanco County laws: search for the Blanco County, Texas code of ordinances
- Travis County website: https://www.traviscountytx.gov/
- Travis County laws: search for the Travis County, Texas code of ordinances
State legislative districts
| State senate district | Share of ZIP residents |
|---|---|
| State Senate District 25 | 98% |
| State Senate District 24 | 1.8% |
| State house district | Share of ZIP residents |
|---|---|
| State House District 19 | 95% |
| State House District 73 | 4.9% |
Voting precincts
4 voting precincts overlap ZIP 78663. 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:78663")
ZIP 78663 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.