Everything You Need to Know About the Mexico-United States Border

4/17/2018 - Associate Professor of History Rachel St. John in History.

The border between the United States and Mexico stretches for nearly 2,000 miles from the Gulf of Mexico to the Pacific Ocean and touches the states of CaliforniaArizonaNew Mexico and Texas. The Rio Grande runs along 1,254 miles of the border, but west of El Paso, Texas, the boundary lacks a natural geographic barrier except for a small stretch along the Colorado River.

The modern border took shape following the Mexican-American War. While the Rio Grande formed the dividing line between Texas and Mexico, the border originally moved west from El Paso on a straight line to the Gila River and then on another straight line to the Pacific Ocean south of San Diego. Following the Gadsden Purchase of 1853, the borders of Arizona and New Mexico moved further south from the Gila River.

A team of surveyors, soldiers and officials from both countries staked out the border from El Paso to Tijuana. According to Rachel St. John, an associate professor of history at UC Davis and author of Line in the Sand: A History of the Western U.S.-Mexico Border, the joint boundary commission underestimated the cost and time it would take to complete the project through such an inhospitable terrain of mountains, canyons and desert. Not until the late 1850s did the boundary commission complete its work.

Read the full story in History.