The Ouachita were a Native American tribe of Algonquin Speaking people who are decendants of Caddo, Son of Diklah, Son of Joktan, Son of Eber, Son of Salah, Son of Arphazad, Son of Shem, Noah′s Son. The sons of Caddo originally settled in th Coastal Plains Region inf the four state area including: Arkansas, Louisiana, Oklahoma and Texas. The Ouachita chose the make their homeland along the lower reaches of the Ouachita River in the area now known as northeastern Louisiana; and they also established villages along the Black River.

One of the primary settlements of the Ouachita was at Pargoud Landing on the Ouachita River, which settlement later became the site of a French Trading post, and eventually the present-day city of Monroe, Louisiana.

Jean-Baptiste Le Moyne, Sieur de Bienville, a French-Canadian colonizer, encountered the Ouachita people in 1700. He first met members of the tribe transporting salt to the Taensa. The Frenchman Bienville then traveled to the principal Ouachita village, which he described as housing 70 people in five houses. Later, by the 1720s, the Ouachita indigenous people assimilated into the Natchitoches tribe.

The descendants of the Ouachita Native American are enrolled in the Caddo Nation of Oklahoma.

The Ouachita tribe became known among English speakers as the Washita tribe; both spellings are transliterations in European languages (French and English, respectively) of the pronunciation of their Caddo name. Sometimes, the Ouachita may also be known as the Yesito.

The name Ouachita is claimed to come from the word ouac meaning buffalo and chito meaning large and together has the meaning of Country of large buffaloes. Once, many moons ago, large heards of buffalo inhabited the lowland valleys of the Ouachita Mountains.

The caddo word washita has the meaning of Good Hunting Ground.

The Ouachita Mountains of Oklahoma and Arkansas and Ouachita River of Arkansas and Louisiana were named for the tribe, as was Lake Ouachita. The Washita River, Ouachita Parish, Louisiana, and Washita County, Oklahoma, were also named for the tribe, as well as the town of Washita, Oklahoma.