With US troops occupying Mexico City, the Mexican government agreed to surrender half of its national territory to the United States. Treaty negotiators had to redraw the line between their countries. For half of the nearly 2,000-mile boundary, they drew it from the Gulf of Mexico to El Paso along the Rio Grande. Thus, a free-flowing river became an international boundary. As the river changed course, would the treaty hold?
Last updated: December 16, 2021