| Irwin, IA (City) |
| Irwin County, GA (County) |
| Irwin Township, PA (Township) |
| Irwindale, CA (City) |
| Irwinton, GA (City) |
| Isabel, KS (City) |
| Isabel, ND (Township) |
| Isabel, SD (City) |
| Isabel Township, IL (Township) |
| Isabella County, MI (County) |
| Isabella Township, MI (Township) |
| Isabelle Town, WI (Town) |
| Isanti, MN (City) |
| Isanti, MN (Township) |
| Isanti County, MN (County) |
