Hernando de Alarcón (born c. 1500) was a Spanish explorer and navigator of the 16th century, noted for having led an early expedition to the Baja California Peninsula, during which he became one of the first Europeans to ascend the Colorado River from its mouth and perhaps the first to reach Alta California.Little is known about Alarcón's life outside of his exploits in New Spain. He was probably born in the town of Trujillo, in present-day Extremadura, Spain, in the first years of the 16th century and traveled to the Spanish colonies in the Americas as a young man.