United States – Mexico border

The Mexico–United States border is an international border separating Mexico and the United States extending from the Pacific Ocean in the west to the Gulf of Mexico to the east. The border traverses a variety of terrains, ranging from major urban areas to uninhabitable deserts. As of 2010^[update] approximately 350 million legal crossings occur annually, and is the most frequently crossed border in the world.

The total length of the continental border is 3,201 kilometers (1,989 mi). From the Gulf of Mexico, it follows the course of the Rio Grande (Río Bravo del Norte) to the border crossing at Ciudad Juárez, Chihuahua and El Paso, Texas; westward from El Paso-Juarez, it crosses vast tracts of the Chihuahuan and Sonoran Deserts to the Colorado River Delta, westward to San Diego-Tijuana, before reaching the Pacific Ocean.

Following the Boundary Treaty of 1970 between the United States and Mexico that settled all the pending boundary disputes and uncertainties related to the Rio Grande (Río Bravo del Norte) border, the national continental border extends 3,145 kilometers (1,954 mi), excluding the maritime boundaries of 29 km (18 mi) in the Pacific Ocean and 19 km (12 mi) in the Gulf of Mexico.

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