Fort Duncan Shaped Eagle Pass From the Start

The U.S. Army built Fort Duncan on March 27, 1849, on the Rio Grande to guard against Apache and Comanche raids and to secure the international border. The fort was located two miles upstream from the old smuggler's trail crossing called El Paso del Águila. Its presence drew traders and settlers, and by 1850 a trading post had opened below the post.

During the Civil War, Confederate forces held the fort. After the war ended, a group of Confederate soldiers known as the Shelby expedition crossed the Rio Grande at Eagle Pass and buried what is described as the last flag flown over Confederate troops in the river. The fort's site in Eagle Pass is now a city park. Understanding this military history helps explain why Eagle Pass developed where it did and why the border crossing here has been active for over 175 years.