The El Camino Real de los Tejas National Historic Trail is a National Historic Trail covering the U.S. section of the El Camino Real de Los Tejas from 17th century Spanish colonial era in Spanish Texas. The National Park Service designated the El Camino Real de los Tejas National Historic Trail as a unit in the National Historic Trail system in 2004.The modern highways Texas 21 (along with Texas OSR) and Louisiana 6 roughly follow the original route of the trail.
The historic trail ran from the capitol and central Viceroyalty of New Spain present day Mexico City winding through Saltillo, Monterrey, Laredo (on the modern Texas border), San Antonio, and Nacogdoches, ending at Natchitoches in modern Louisiana.The trail has a 2,500 mile length. For centuries the Native Americans had used the trail routes for trading between the Great Plains and Chihuahuan Desert regions. The El Camino Real de Los Tejas was first followed and marked by Spanish explorers and missionaries in the 1700s. It was one of several El Camino Real, or 'royal roads,' that connected the more Spanish possessions in North America with Mexico City.