Boundary Atlas

ZIP code 02121: Boston, MA

ZIP code 02121 is in Boston, in Suffolk County, Massachusetts. It is in Massachusetts's 7th congressional district. Its state senate districts are Second Suffolk District (97%) and First Suffolk District (2.7%); its state house districts are 5th Suffolk District (62%), 6th Suffolk District (21%) and 7th Suffolk District (17%).

28,766residents (2020 Census)
1.9 sq miland area
1cities and towns
1congressional district
15voting precincts

See it on the mapAll of Massachusetts

City and county

City or townShare of ZIP residents
Boston100%

CountyShare of ZIP residents
Suffolk County100%

Town or county subdivisionShare of ZIP residents
Boston city100%

Congressional district

Congressional districtShare of ZIP residents
Massachusetts's 7th congressional district (MA-07)100%

State legislative districts

State senate districtShare of ZIP residents
Second Suffolk District97%
First Suffolk District2.7%

State house districtShare of ZIP residents
5th Suffolk District62%
6th Suffolk District21%
7th Suffolk District17%

Voting precincts

15 voting precincts overlap ZIP 02121. 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:02121")

ZIP 02121 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.