Boundary Atlas

ZIP code 51645: Monroe, IA

ZIP code 51645 is in Imogene (18% of residents), in Fremont County (68%), Mills County (30%), Page County (1.8%) and Montgomery County (<0.1%), Iowa. 82% of its residents live outside city limits. It is in Iowa's 4th congressional district (98%) and Iowa's 3rd congressional district (1.8%). Its state senate districts are State Senate District 8 (98%) and State Senate District 9 (1.8%); its state house districts are State House District 16 (98%) and State House District 18 (1.8%).

219residents (2020 Census)
45.1 sq miland area
1cities and towns
2congressional districts
4voting precincts

See it on the mapAll of Iowa

City and county

City or townShare of ZIP residents
Imogene18%

CountyShare of ZIP residents
Fremont County68%
Mills County30%
Page County1.8%
Montgomery Countyland only

Town or county subdivisionShare of ZIP residents
Monroe township68%
Deer Creek township30%
Pierce township1.8%
West townshipland only

Congressional districts

Congressional districtShare of ZIP residents
Iowa's 4th congressional district (IA-04)98%
Iowa's 3rd congressional district (IA-03)1.8%

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 898%
State Senate District 91.8%

State house districtShare of ZIP residents
State House District 1698%
State House District 181.8%

Voting precincts

4 voting precincts overlap ZIP 51645. 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:51645")

ZIP 51645 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.