Boundary Atlas

ZIP code 02421: Lexington, MA

ZIP code 02421 is in Lexington, in Middlesex County, Massachusetts. It is in Massachusetts's 5th congressional district. Its state senate districts are Third Middlesex District (58%) and Fourth Middlesex District (42%); its state house districts are 15th Middlesex District (99%) and 21st Middlesex District (0.8%).

18,950residents (2020 Census)
9.6 sq miland area
1cities and towns
1congressional district
8voting precincts

See it on the mapAll of Massachusetts

City and county

City or townShare of ZIP residents
Lexington100%

CountyShare of ZIP residents
Middlesex County100%

Town or county subdivisionShare of ZIP residents
Lexington town100%

Congressional district

Congressional districtShare of ZIP residents
Massachusetts's 5th congressional district (MA-05)100%

State legislative districts

State senate districtShare of ZIP residents
Third Middlesex District58%
Fourth Middlesex District42%

State house districtShare of ZIP residents
15th Middlesex District99%
21st Middlesex District0.8%

Voting precincts

8 voting precincts overlap ZIP 02421. 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:02421")

ZIP 02421 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.