Boundary Atlas

Illinois's 12th congressional district (IL-12)

Illinois's 12th congressional district (IL-12) covers parts or all of 34 counties, including Alexander County, Clark County, Clay County, Clinton County, Crawford County and Cumberland County, and 286 ZIP codes (245 wholly inside it). Its 2020 population was 753,677. This is the map in force for the November 3, 2026 election.

753,677residents (2020 Census)
34counties
286ZIP codes
846voting precincts

Who represents IL-12

OfficeMemberContact
U.S. Representative (IL-12)Mike Bost (R)202-225-5661
U.S. SenatorRichard J. Durbin (D)202-224-2152 · contact form
U.S. SenatorTammy Duckworth (D)202-224-2854 · contact form

Officials serving now (members of Congress until January 3, 2027). Sources: Members of Congress: the @unitedstates project, congress-legislators (CC0).

Counties

CountyShare of the county's residents in IL-12
Alexander County100%
Clark County100%
Clay County100%
Clinton County100%
Crawford County100%
Cumberland County100%
Edwards County100%
Effingham County100%
Franklin County100%
Gallatin County100%
Hamilton County100%
Hardin County100%
Jackson County100%
Jasper County100%
Jefferson County100%
Johnson County100%
Lawrence County100%
Marion County100%
Massac County100%
Monroe County100%
Perry County100%
Pope County100%
Pulaski County100%
Randolph County100%
Richland County100%
Saline County100%
Union County100%
Wabash County100%
Washington County100%
Wayne County100%
White County100%
Williamson County100%
St. Clair County36%
Coles County24%

ZIP codes

Percentages mark ZIPs only partly in IL-12: the share of that ZIP's residents inside it.

Towns

Adkins precinct, Albion No. 1 precinct, Albion No. 2 precinct, Albion No. 3 precinct, Allison township, Alma township, Alto Pass precinct, America precinct, Anderson township, Anna District 1 precinct, Anna District 2 precinct, Anna District 3 precinct, Anna District 4 precinct, Anna District 5 precinct, Anna District 6 precinct, Anna District 7 precinct, Arrington township, Asbury township, Ashley township, Ashmore township, Auburn township, Balcom precinct, Bald Hill township, Baldwin precinct, Banner township, Barnhill township, Barren township, Beaucoup precinct, Beaucoup township, Beaver Creek township, Bedford township, Belknap precinct, Bellmont precinct, Benton precinct, Benton township, Berry township, Bible Grove township, Big Mound township, Bishop township and Blair township and others.

Get this in your AI agent

Your agent can draw every precinct in IL-12, or list them with population shares (related_geographies). Add https://boundarymcp.com/mcp to Claude, ChatGPT, Cursor or Codex (free, no key; how), then:

get_boundaries(id="us:congressional_district:1712", children_level="precinct", include_districts=True)