ZIP code 21791: District 12, Union Bridge, MD
ZIP code 21791 is in Union Bridge (18% of residents) and Libertytown (5.8%), in Carroll County (53%) and Frederick County (47%), Maryland. 76% of its residents live outside city limits. It is in Maryland's 2nd congressional district (53%) and Maryland's 6th congressional district (47%). Its state senate districts are State Senate District 5 (53%) and State Senate District 4 (47%); its state house districts are State Legislative District 5 (53%) and State Legislative District 4 (47%).
See it on the mapAll of Maryland
City and county
| City or town | Share of ZIP residents |
|---|---|
| Union Bridge | 18% |
| Libertytown | 5.8% |
| County | Share of ZIP residents |
|---|---|
| Carroll County | 53% |
| Frederick County | 47% |
| Town or county subdivision | Share of ZIP residents |
|---|---|
| District 12, Union Bridge | 29% |
| District 17, Johnsville | 25% |
| District 2, Uniontown | 21% |
| District 8, Liberty | 17% |
| District 19, Linganore | 4.9% |
| District 10, Middleburg | 2.0% |
| District 11, New Windsor | 1.2% |
Congressional districts
| Congressional district | Share of ZIP residents |
|---|---|
| Maryland's 2nd congressional district (MD-02) | 53% |
| Maryland's 6th congressional district (MD-06) | 47% |
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 (MD-02) | Johnny Olszewski, Jr. (D) | 202-225-3061 | 53% |
| U.S. Representative (MD-06) | April McClain Delaney (D) | 202-225-2721 | 47% |
| U.S. Senator | Angela D. Alsobrooks (D) | 202-224-4524 · contact form | statewide |
| U.S. Senator | Chris Van Hollen (D) | 202-224-4654 · contact form | statewide |
| State Senator (State Senate District 5) | Justin Ready (R) | 53% | |
| State Senator (State Senate District 4) | Bill Folden (R) | 47% | |
| Delegate (State Legislative District 5) | April Rose (R) | 53% | |
| Delegate (State Legislative District 5) | Chris Tomlinson (R) | 53% | |
| Delegate (State Legislative District 5) | Christopher Bouchat (R) | 53% | |
| Delegate (State Legislative District 4) | April Miller (R) | 47% | |
| Delegate (State Legislative District 4) | Barrie Ciliberti (R) | 47% | |
| Delegate (State Legislative District 4) | Jesse Pippy (R) | 47% |
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
- Union Bridge website: http://www.carr.org/~unionbr
- Union Bridge laws: search for the Union Bridge, Maryland code of ordinances
- Libertytown laws: search for the Libertytown, Maryland code of ordinances
- Carroll County website: https://www.carrollcountymd.gov/
- Carroll County laws: search for the Carroll County, Maryland code of ordinances
- Frederick County website: http://FrederickCountyMD.gov/
- Frederick County laws: search for the Frederick County, Maryland code of ordinances
State legislative districts
| State senate district | Share of ZIP residents |
|---|---|
| State Senate District 5 | 53% |
| State Senate District 4 | 47% |
| State house district | Share of ZIP residents |
|---|---|
| State Legislative District 5 | 53% |
| State Legislative District 4 | 47% |
Voting precincts
7 voting precincts overlap ZIP 21791. 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:21791")
ZIP 21791 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.