For more than 100 years a continuous debate over the land known as the Chamizal - 600 acres between the bed of the Rio Grande in 1852 and the present channel of the river - haunted the territory surrounding El Paso, straining relations between the United States and Mexico. The 1848 Treaty of Guadalupe Hidalgo and the Treaty of 1884 set the Mexico/United States border down the middle of the Rio Grande along its deepest channel. However, controversy arose because of continual channel shifting caused by repetitive flooding. According to the initial treaties, the Chamizal belonged to the United States, but after several rounds of arbitration spanning more than 50 years, President John F. Kennedy agreed to divide the territory. The conclusion was officially marked in 1964 with a ceremonial meeting between Mexican President Adolfo López Mateos and U.S. President Lyndon B. Johnson.

Commemorating that peaceful diplomatic success, the Chamizal National Monument offers exhibits and bicultural art shows and performances to celebrate Mexican and American cooperation. It is also the only national park that flies the flags of both the U.S. and Mexico.