Boundary Atlas

ZIP code 61360: Seneca, IL

ZIP code 61360 is in Seneca (67% of residents), in LaSalle County (96%) and Grundy County (3.8%), Illinois. 33% of its residents live outside city limits. It is in Illinois's 14th congressional district (81%) and Illinois's 16th congressional district (19%). Its state senate districts are State Senate District 38 (50%) and State Senate District 53 (50%); its state house districts are State House District 75 (50%) and State House District 106 (50%).

3,306residents (2020 Census)
47.4 sq miland area
1cities and towns
2congressional districts
8voting precincts

See it on the mapAll of Illinois

City and county

City or townShare of ZIP residents
Seneca67%

CountyShare of ZIP residents
LaSalle County96%
Grundy County3.8%

Town or county subdivisionShare of ZIP residents
Manlius township70%
Brookfield township15%
Miller township9.0%
Norman township1.8%
Mission township1.6%
Nettle Creek township1.0%
Vienna township1.0%

Congressional districts

Congressional districtShare of ZIP residents
Illinois's 14th congressional district (IL-14)81%
Illinois's 16th congressional district (IL-16)19%

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.

State legislative districts

State senate districtShare of ZIP residents
State Senate District 3850%
State Senate District 5350%

State house districtShare of ZIP residents
State House District 7550%
State House District 10650%

Voting precincts

8 voting precincts overlap ZIP 61360. 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:61360")

ZIP 61360 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.