Who explored much of the southwestern US?

Many explorers contributed to the exploration of the southwestern United States, but one of the most notable was John C. Frémont. In the 1840s, he led several expeditions that mapped large areas of the region, providing valuable information about its geography and resources. Additionally, the Spanish explorer Francisco Vázquez de Coronado is known for his early exploration of the area in the 16th century, seeking the fabled Seven Cities of Gold. Their explorations helped pave the way for westward expansion and settlement.