Boundary Atlas

ZIP code 21005: Aberdeen Proving Ground, MD

ZIP code 21005 is in Aberdeen Proving Ground (98% of residents), in Harford County, Maryland. It is in Maryland's 1st congressional district. Its state senate district is State Senate District 34; its state house district is State Legislative Subdistrict 34A.

1,709residents (2020 Census)
33.4 sq miland area
1cities and towns
1congressional district
1voting precincts

See it on the mapAll of Maryland

City and county

City or townShare of ZIP residents
Aberdeen Proving Ground98%

CountyShare of ZIP residents
Harford County100%

Town or county subdivisionShare of ZIP residents
District 2, Halls Cross Roads100%

Congressional district

Congressional districtShare of ZIP residents
Maryland's 1st congressional district (MD-01)100%

State legislative districts

State senate districtShare of ZIP residents
State Senate District 34100%

State house districtShare of ZIP residents
State Legislative Subdistrict 34A100%

Voting precincts

1 voting precinct overlap ZIP 21005. 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:21005")

ZIP 21005 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.