Indiana Watershed
"A watershed is an area of land that drains all the streams and rainfall to a common outlet such as the outflow of a reservoir, mouth of a bay, or any point along a stream channel."
- United States Geological Survey
USGS defines watersheds in a variety of sizes, from large ones like the Ohio River watershed, down to watersheds that cover much smaller areas. The watersheds in the list that follows are called 8-digit hydrologic units; the scans in the individual watershed accounts in the links below come from this 1974 USGS Map of 8-Digit Hydrologic Units of Indiana. The 38 listed below include all of those that occupy some part of Indiana, with the exception of the hydrologic unit that comprises Lake Michigan.
Auglaize
Blue-Sinking
Chicago
Driftwood
Flatrock-Haw
Highland-Pigeon
Iroquois
Kankakee
Little Calumet-Galien
Lower East Fork White
Lower Great Miami
Lower Ohio-Little Pigeon
Lower Wabash
Lower White
Middle Ohio-Laughery
Middle Wabash-Busseron
Middle Wabash-Deer
Middle Wabash-Little Vermillion
Mississinewa
Muscatatuck
Northern Eel
Patoka
Salamonie
Silver-Little Kentucky
Southern Eel
St Joseph (Michigan)
St Joseph-Maumee
St Marys
Sugar
Tippecanoe
Upper East Fork White
Upper Great Miami
Upper Maumee
Upper Wabash
Upper White
Vermillion
Whitewater
Wildcat