Karankawa, several groups of North American Indians that lived along the Gulf of Mexico in Texas, from about Galveston Bay to Corpus Christi Bay. They were first encountered by the French explorer La Salle in the late 17th century, and their rapid decline began with the arrival of Stephen Austin and other white settlers in the 1820s and 1830s. The Karankawa fought on the side of the Texans in the Texan war of independence.