ZIP code 63366: O'Fallon, MO
ZIP code 63366 is in O'Fallon (78% of residents), St. Paul (5.6%) and Wentzville (3.9%), in St. Charles County, Missouri. 12% of its residents live outside city limits. It is in Missouri's 3rd congressional district (70%) and Missouri's 2nd congressional district (30%). Its state senate districts are State Senate District 2 (95%), State Senate District 10 (3.9%) and State Senate District 23 (1.0%); its state house districts are State House District 103 (50%), State House District 64 (43%), State House District 63 (3.9%), State House District 108 (2.3%) and State House District 65 (0.8%).
See it on the mapAll of Missouri
City and county
| City or town | Share of ZIP residents |
|---|---|
| O'Fallon | 78% |
| St. Paul | 5.6% |
| Wentzville | 3.9% |
| St. Peters | 0.8% |
| Josephville | 0.2% |
| Dardenne Prairie | <0.1% |
| County | Share of ZIP residents |
|---|---|
| St. Charles County | 100% |
| Town or county subdivision | Share of ZIP residents |
|---|---|
| Wentzville township | 37% |
| O'Fallon township | 22% |
| Lake St. Louis township | 21% |
| Weldon Spring township | 15% |
| Dardenne township | 5.5% |
| Rivers township | 0.1% |
Congressional districts
| Congressional district | Share of ZIP residents |
|---|---|
| Missouri's 3rd congressional district (MO-03) | 70% |
| Missouri's 2nd congressional district (MO-02) | 30% |
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 (MO-03) | Robert F. Onder, Jr. (R) | 202-225-2956 | 70% |
| U.S. Representative (MO-02) | Ann Wagner (R) | 202-225-1621 | 30% |
| U.S. Senator | Eric Schmitt (R) | 202-224-5721 · contact form | statewide |
| U.S. Senator | Josh Hawley (R) | 202-224-6154 · contact form | statewide |
| State Senator (State Senate District 2) | Nick Schroer (R) | 95% | |
| State Senator (State Senate District 23) | Adam Schnelting (R) | 1.0% | |
| State Representative (State House District 103) | Dave Hinman (R) | 50% | |
| State Representative (State House District 64) | Deanna Self (R) | 43% | |
| State Representative (State House District 63) | Tricia Byrnes (R) | 3.9% | |
| State Representative (State House District 108) | Mike Costlow (R) | 2.3% | |
| State Representative (State House District 65) | Wendy Hausman (R) | 0.8% |
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
- O'Fallon website: http://www.ofallon.mo.us/
- O'Fallon laws: search for the O'Fallon, Missouri code of ordinances
- St. Paul website: http://www.cityofstpaulmissouri.com/
- St. Paul laws: search for the St. Paul, Missouri code of ordinances
- Wentzville website: http://www.wentzvillemo.org/
- Wentzville laws: search for the Wentzville, Missouri code of ordinances
- St. Charles County website: http://www.sccmo.org
- St. Charles County laws: search for the St. Charles County, Missouri code of ordinances
State legislative districts
| State senate district | Share of ZIP residents |
|---|---|
| State Senate District 2 | 95% |
| State Senate District 10 | 3.9% |
| State Senate District 23 | 1.0% |
| State house district | Share of ZIP residents |
|---|---|
| State House District 103 | 50% |
| State House District 64 | 43% |
| State House District 63 | 3.9% |
| State House District 108 | 2.3% |
| State House District 65 | 0.8% |
Voting precincts
19 voting precincts overlap ZIP 63366. 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:63366")
ZIP 63366 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.