The Guaycura (Waicura, Waikuri, Guaycuri) were a native people of Baja California Sur, Mexico, occupying an area extending south from near Loreto to Todos Santos They contested the area around La Paz with the Pericú. The Guaycura were nomadic hunter-gatherers. They are distinguished by a language unrelated to any other Native American language, indicating in the opinion of some linguists that their ancestry in Baja California dates back thousands of years.
The Society of Jesus (Jesuits) of the Catholic Church established Christian missions in their territory in the 18th century. The Guaycura may have numbered 5,000 at the time of Spanish contact, but their numbers quickly declined, mostly due to European diseases. They became extinct as a culture by about 1800, the survivors being absorbed into the mestizo society of Mexico.
Linguists and archaeologists speculate that the Guaycura and the Pericú occupying the southern tip of the Baja California peninsula may have been the descendants of very early Native American migrants to the Americas. Their languages apparently were not related to each other or any other languages and their physical type was uncommon among Native Americans. They were small-bodied and long-headed (dolichocephalic). Their geographical location was a cul-de-sac in which they may have been isolated from extensive interaction with other peoples. Thus, their unique languages and physical characteristics may have survived for thousands of years. The lack of relationships between Guaycura and other languages indicates that Guaycura may have developed in isolation over a period of at least 5,000 years. At one time the Guaycura and Pericú may have occupied much greater territories but they were pushed southward and isolated by the expansion of the Cochimí people who spoke a language in the Yuman-Cochimí language family.