ZIP code 21161: District 4, Marshall, MD
ZIP code 21161 is in Harford County (52%) and Baltimore County (48%), Maryland, outside any city or Census-designated place. It is in Maryland's 1st congressional district. Its state senate districts are State Senate District 7 (52%) and State Senate District 42 (48%); its state house districts are State Legislative Subdistrict 7B (52%) and State Legislative Subdistrict 42A (48%).
See it on the mapAll of Maryland
City and county
Outside any city or Census-designated place.
| County | Share of ZIP residents |
|---|---|
| Harford County | 52% |
| Baltimore County | 48% |
| Town or county subdivision | Share of ZIP residents |
|---|---|
| District 4, Marshall | 52% |
| District 7 | 41% |
| District 10 | 6.1% |
Congressional district
| Congressional district | Share of ZIP residents |
|---|---|
| Maryland's 1st congressional district (MD-01) | 100% |
Elected officials
| Office | Member | Contact | Share of residents |
|---|---|---|---|
| U.S. Representative (MD-01) | Andy Harris (R) | 202-225-5311 | 100% |
| 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 7) | J.B. Jennings (R) | 410-870-5848 | 52% |
| State Senator (State Senate District 42) | Chris West (R) | 48% | |
| Delegate (State Legislative Subdistrict 7B) | Lauren Arikan (R) | 52% | |
| Delegate (State Legislative Subdistrict 42A) | Alex Harlan (R) | 48% |
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
- Harford County website: https://www.harfordcountymd.gov/
- Harford County laws: search for the Harford County, Maryland code of ordinances
- Baltimore County website: https://www.baltimorecountymd.gov/
- Baltimore County laws: search for the Baltimore County, Maryland code of ordinances
State legislative districts
| State senate district | Share of ZIP residents |
|---|---|
| State Senate District 7 | 52% |
| State Senate District 42 | 48% |
| State house district | Share of ZIP residents |
|---|---|
| State Legislative Subdistrict 7B | 52% |
| State Legislative Subdistrict 42A | 48% |
Voting precincts
6 voting precincts overlap ZIP 21161. 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:21161")
ZIP 21161 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.