ZIP code 78599 is in Weslaco (42% of residents), Olivarez (13%), Midway North (11%) and Mila Doce (5.4%), in Hidalgo County, Texas. 28% of its residents live outside city limits. It is in Texas's 15th congressional district. Its state senate district is State Senate District 27; its state house districts are State House District 39 (78%), State House District 35 (19%) and State House District 40 (3.8%).
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: Mayors: Open States (public domain); State legislators: Open States (public domain); Members of Congress: the @unitedstates project, congress-legislators (CC0).
13 voting precincts overlap ZIP 78599.
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:78599")
ZIP 78599 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.