Quapaw (kwôˈpô) [key], Native North Americans, also called the Arkansas, whose language belongs to the Siouan branch of the Hokan-Siouan linguistic stock (see Native American languages). The Quapaw were essentially of the Plains culture, but they had other distinctive traits; they built temple and burial mounds and lived in longhouses. They once lived with the Omaha, the Kansa, the Ponca, and the Osage in the Ohio Valley, but when the groups separated the Quapaw migrated down the Mississippi River. Jacques Marquette, who arrived at their village in 1673, was the first of many French explorers to visit the Quapaw. They made a large land cession to the United States in 1818, and later moved to Oklahoma, where they lived on a reservation. In 1990 there were some 1,400 Quapaw in the United States.