Alarcón, Hernando de (ārnänˈdō dā älärkōnˈ) [key], fl. 1540, Spanish explorer in the Southwest. He was given command of a fleet that was supposed to support the land expedition of Francisco Vásquez de Coronado. In the summer of 1540 he sailed up the Gulf of California; proved definitely that Lower California was a peninsula, not an island; and discovered the Colorado River. He failed, however, to make contact with Coronado's expedition. He explored the river a few months before García López de Cárdenas discovered the Grand Canyon.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.