The Rio Grande as Border

The Rio Grande just west of Las Cruces is not a dramatic river. In most seasons it runs slow and shallow here, maybe knee-deep in late summer, narrower than a four-lane road. You could wade across it. And yet this same river, about forty miles farther south, becomes one of the most significant political lines in North America: the international border between the United States and Mexico.

The Treaty of Guadalupe Hidalgo, signed February second, eighteen forty-eight, established the Rio Grande as the boundary between the two countries from its mouth at the Gulf of Mexico to a point near El Paso del Norte. But rivers move. The Rio Grande has shifted course dozens of times over the past century and a half, creating chronic disputes about which side of the channel a given patch of land belongs to.

The most famous of these disputes involved a meander loop called El Chamizal, about forty miles south of here in El Paso. The river shifted north in the eighteen sixty-four flood, transferring roughly six hundred acres of Mexican territory to the American side. Mexico protested for decades. The dispute was not finally resolved until nineteen sixty-three, when President Kennedy and Mexican President Adolfo Lopez Mateos signed the Chamizal Convention. The land was returned. The river was straightened and cemented into a permanent channel.

Along the Las Cruces stretch, the river's water is governed by the Convention of nineteen oh six, which allocated Rio Grande water between the United States and Mexico. Elephant Butte Reservoir, built in nineteen sixteen, stores that water, and the international allocation determines how much reaches Mexico in any given year. Drought years produce intense diplomacy.

The communities on either side of the river farther south, El Paso and Ciudad Juarez, form a binational metropolitan area of more than two million people. The border is a line on a map, but the economy, the culture, and the family ties cross it constantly.