| Ahnapee River | |
| Subdivision Type1: | Country |
| Subdivision Name1: | United States |
| Subdivision Type2: | State |
| Subdivision Name2: | Wisconsin |
| Subdivision Type3: | Region |
| Subdivision Name3: | Door Peninsula |
| Length: | 15miles |
| Source1: | Gardner Swamp |
| Source1 Location: | Wisconsin |
| Source1 Coordinates: | 44.7689°N -87.5392°W |
| Mouth: | Lake Michigan |
| Mouth Location: | Algoma, Wisconsin |
| Mouth Coordinates: | 44.6083°N -87.4331°W |
| Tributaries Left: | Silver Creek |
The Ahnapee River is a 14.7adj=midNaNadj=mid[1] river on the Door Peninsula in eastern Wisconsin in the United States. It rises in Door County, Wisconsin, and flows through Kewaunee County into Lake Michigan at the city of Algoma. Its name has been ascribed as coming from the Ojibwe word aanapii meaning "when?".
The Ahnapee rises in southern Door County and flows generally southeastwardly into northeastern Kewaunee County, past the village of Forestville, where it is dammed. Downstream of Forestville the river becomes a freshwater estuary of Lake Michigan and is paralleled by a rail trail called the Ahnapee State Trail.[2] It joins Lake Michigan at the city of Algoma.[3] The length of the river from Forestville to Algoma has ten public access points.[4]