When did Spain start founding colonies in what is now the American Southwest?

The first colony in the American Southwest was founded in present-day New Mexico in 1598 by Juan de (Mate (c. 1550, c. 1630).

He is considered the founder of New Mexico, called Nuevo Mexico by the Spanish and treated as a northern province of New Spain. Santa Fe, New Mexico’s capital, was founded in 1609. A mission in Arizona, then considered part of New Mexico, was founded in 1692.

In the eighteenth century, French interest in Texas prompted Spain to found settlements there, including San Antonio in 1718. Rumors of Russian and British designs on California prompted Spain to found San Diego in 1769 and San Francisco in 1776.

Maine, Missouri, and New York each have a town called Mexico.