A presidio is a military settlement generally seen in areas controlled by the Spanish. The word comes from the Latin word "praesidium," which means "garrisoned place." The fourth viceroy of New Spain, Martin Enriquez, first created the presidios of the colonial Southwest United States.
The presidios of the Southwest were rectangular or square and built using local materials, such as stone and adobe. Builders constructed the structures' two diagonal corners with round bastions containing firing ports. Soldiers could fire at any attacker along the four walls from these ports. Several presidios established in the 18th century included San Francisco Xavier de Gigedo, San Elizario and San Luis de las Amarillas.