Where a river starts A branch, stream, creek, spring or tributary.
Nile River
Missouri river
Its source is in Spain.
St. louise river
Missouri RiverMississippi River
Missouri RiverMissouri River; Illinois River
Missouri (and Columbia)
Missouri river
NO. The Missouri river is the tributary
The Missouri River flows into the Mississippi River just north of Saint Louis, Missouri.
The Green River Tributary has its source in the Wind River Mountains.