Map showing the Southwest Trail or Military Road as it was in the mid-1800s (in red) and the Natchitoches Trace that it replaced (in brown).
The Southwest Trail was a 19th-century pioneer route that was the primary route for American settlers bound for Texas.
The Southwest Trail was originally an American Indian trace, and it was improved and expanded by European-American pioneers. The trail ran from St. Louis, Missouri, to Fulton, Arkansas on the Red River. At the time of Americans' first settling the Texas area, the Red River was the border between Mexico and the United States.