The Keya Paha River (/ˈkɪpəhɔː/ KIP-ə-haw) (Pawnee: Rakickatihrihuuru ) is a river flowing 127 miles (204 km) through the U.S. states of South Dakota and Nebraska.The name is derived from the Dakota language ke'-ya pa-ha', meaning "turtle hill". The river's name was given to Keya Paha County, Nebraska, through which it flows.The river originates in Todd County in south central South Dakota, at the confluence of Antelope Creek and Rock Creek near the town of Hidden Timber.