Oñate's last major expedition went to the west, from New Mexico to the lower valley of the Colorado River.
The party of about three dozen men set out from the Rio Grande valley in October 1604.
They traveled by way of Zuñi, the Hopi pueblos, and the Bill Williams River to the Colorado River, and descended that river to its mouth in the Gulf of California in January 1605, before returning along the same route to New Mexico.
The evident purpose of the expedition was to locate a port by which New Mexico could be supplied, as an alternative to the laborious overland route from New Spain.

The expedition to the lower Colorado River was important as the only recorded European incursion into that region between the expeditions of Hernando de Alarcón and Melchior Díaz in 1540, and the visits of Eusebio Francisco Kino beginning in 1701.
The explorers did not see evidence of prehistoric Lake Cahuilla, which must have arisen shortly afterwards in the Salton Sink.

They mistakenly thought that the Gulf of California continued indefinitely to the northwest, giving rise to a belief that was common in the 17th century that the western coasts of an Island of California were what was seen by sailing expeditions in the Pacific.

Native groups observed living on the lower Colorado River, were, from north to south, the Amacava (Mohave), Bahacecha, Osera (Pima), at the confluence of the Gila River with the Colorado, in a location later occupied by the Quechan, Alebdoma.

Seen by Oñate below the Gila junction but subsequently reported upstream from there, in the area where Oñate had encountered the Coguana, or Kahwans, Agalle, and Agalecquamaya, or Halyikwamai, and the Cocopah.

Concerning areas that the explorers had not observed directly, they gave fantastic reports about races of human and areas said to be rich in gold, silver, and pearls.
Oñate's last major expedition went to the west, from New Mexico to the lower valley of the Colorado River. The party of about three dozen men set out from the Rio Grande valley in October 1604. They traveled by way of Zuñi, the Hopi pueblos, and the Bill Williams River to the Colorado River, and descended that river to its mouth in the Gulf of California in January 1605, before returning along the same route to New Mexico. The evident purpose of the expedition was to locate a port by which New Mexico could be supplied, as an alternative to the laborious overland route from New Spain.
The expedition to the lower Colorado River was important as the only recorded European incursion into that region between the expeditions of Hernando de Alarcón and Melchior Díaz in 1540, and the visits of Eusebio Francisco Kino beginning in 1701. The explorers did not see evidence of prehistoric Lake Cahuilla, which must have arisen shortly afterwards in the Salton Sink.
They mistakenly thought that the Gulf of California continued indefinitely to the northwest, giving rise to a belief that was common in the 17th century that the western coasts of an Island of California were what was seen by sailing expeditions in the Pacific.
Native groups observed living on the lower Colorado River, were, from north to south, the Amacava (Mohave), Bahacecha, Osera (Pima), at the confluence of the Gila River with the Colorado, in a location later occupied by the Quechan, Alebdoma.
Seen by Oñate below the Gila junction but subsequently reported upstream from there, in the area where Oñate had encountered the Coguana, or Kahwans, Agalle, and Agalecquamaya, or Halyikwamai, and the Cocopah.
Concerning areas that the explorers had not observed directly, they gave fantastic reports about races of human and areas said to be rich in gold, silver, and pearls.
Juan de Oñate