Mexico–United States 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 in the east. The border traverses a variety of terrains, ranging from urban areas to deserts. The Mexico–United States border is the most frequently crossed border in the world, with approximately 350 million documented crossings annually. It is the tenth-longest border between two countries in the world.