The Treaty of Guadalupe Hidalgo ended the Mexican War in 1848 and designated the main channel of the Rio Grande as the boundary between the U.S. and Mexico. Major William Emory led the border survey from 1849 to 1853. Young Washington D.C. surveyor Thomas W. Jones joined Emory's survey effort at El Paso in 1850. While serving as assistant surveyor of the Lower Rio Grande survey party, Jones drowned nearby on July 23, 1853, and was buried here on Dr. Eli Merriman's Ranch.