Oñate, Juan de (1549?–1624?), a Spanish explorer of the southwestern United States. He established the first European settlement in New Mexico, at San Juan, north of present-day Santa Fe. Oñate was authorized in 1595 by the viceroy in Mexico to colonize and govern the New Mexico region and took possession of it in 1598. Searching for precious metals, he led explorations into what is now Kansas and to the Gulf of California. Conflict developed between Oñate and the Mexican authorities, and in 1607 he resigned as governor. He was convicted of misconduct in office and ordered not to return to New Mexico. He died in Spain while there to appeal his case.