ZIP code 49045: Decatur, MI
ZIP code 49045 is in Decatur (31% of residents), in Van Buren County (91%) and Cass County (9.0%), Michigan. 69% of its residents live outside city limits. It is in Michigan's 4th congressional district (91%) and Michigan's 5th congressional district (9.0%). Its state senate districts are State Senate District 20 (91%) and State Senate District 17 (9.0%); its state house districts are State House District 39 (91%), State House District 36 (8.1%) and State House District 37 (0.9%).
See it on the mapAll of Michigan
City and county
| City or town | Share of ZIP residents |
|---|---|
| Decatur | 31% |
| County | Share of ZIP residents |
|---|---|
| Van Buren County | 91% |
| Cass County | 9.0% |
| Town or county subdivision | Share of ZIP residents |
|---|---|
| Decatur township | 60% |
| Hamilton township | 24% |
| Volinia township | 7.4% |
| Keeler township | 5.1% |
| Lawrence township | 1.0% |
| Wayne township | 0.9% |
| Marcellus township | 0.7% |
| Paw Paw township | 0.7% |
Congressional districts
| Congressional district | Share of ZIP residents |
|---|---|
| Michigan's 4th congressional district (MI-04) | 91% |
| Michigan's 5th congressional district (MI-05) | 9.0% |
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 district | Share of ZIP residents |
|---|---|
| State Senate District 20 | 91% |
| State Senate District 17 | 9.0% |
| State house district | Share of ZIP residents |
|---|---|
| State House District 39 | 91% |
| State House District 36 | 8.1% |
| State House District 37 | 0.9% |
Voting precincts
8 voting precincts overlap ZIP 49045. 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:49045")
ZIP 49045 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.