Osage is a city in Mitchell County, Iowa, United States. The population was 3,451 at the 2000 census. It is the county seat of Mitchell County.
Osage is located at 43°17′5″N 92°48′44″W / 43.28472°N 92.81222°W / 43.28472; -92.81222 (43.284618, -92.812129).
According to the United States Census Bureau, the city has a total area of 2.1 square miles (5.4 km²), all of it land.