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–U.S. border is the most frequently crossed border in the world with approximately 350 million documented crossings annually. Illegal crossing of the border to enter the United States has been a top issue in the States and is causing a border crisis. It is one of two international borders that the United States has, the other being the Canada–United States border to the north. It is the tenth-longest border between two countries in the world.