Thornapple River

Thornapple River
Enhanced USGS Satellite Image, Thornapple River drainage basin.
Native name
  • Sowanquesake (Ottawa)
  • Tomba-Signe
Location
CountryUnited States
StateMichigan
CountiesDrainage basin covers portions of Barry, Eaton, Ionia, and Kent Counties in Central Michigan
Physical characteristics
Source 
  locationS of Boody Lake, Eaton Township, Eaton County, Michigan
Mouth 
  location
Grand River, Ada Township, Kent County, Michigan
  elevation
617 ft (188 m)
Length88 mi (142 km)
Discharge 
  locationmouth
  average838.49 cu ft/s (23.743 m3/s) (estimate)

The Thornapple River (Ottawa: Sowanquesake, "Forked River") (GNIS ID #1075813) is an 88.1-mile-long (141.8 km) tributary of Michigan's longest river, the Grand River. The Thornapple rises in Eaton County, Michigan and drains a primarily rural farming area in Central Michigan. It joins the Grand in Ada, Michigan, 10 miles (16 km) east of Grand Rapids.