El Presidio Historic District is one of six divisions of downtown Tucson, Arizona. The district derives its name from El Presidio San Agustin del Tucson, an eighteenth-century Spanish presidio, or fort. Hugh O'Connor, also known as El Capitan Colorado or the Red Captain, was an Irish lieutenant colonel serving the Spanish crown in Mexico.

In August 1775, O'Connor selected a site on the Santa Cruz River's eastern shore for a new presidio in the Mexican province of Sonora. Native Americans had lived on the site since prehistoric times, and the village which grew around the presidio became a vibrant mixture of Native, Spanish, and later Anglo-American cultures. After the United States won control of Arizona in the 1840s, settlers used the presidio's adobe blocks to construct new homes.

Today, a recreation of part of the original presidio stands in the historic district. Tucson residents enjoy occasional "Living History" exhibits at the presidio, featuring Spanish colonial costuming, military drills, and food from an adobe oven. Most of the neighboring buildings date from the American Territorial period, and are a mixture of Anglo and Spanish styles. The Tucson Museum of Art and family-owned Mexican restaurants also await visitors to El Presidio Historic District.