How many people are caught each year trying to cross into the United States from Mexico without proper documents?

The U.S. Border Patrol catches about one million people each year without documents proving their legal status, sending most of them back to Mexico.

Most are Mexicans, though some come from other parts of Latin America, particularly Central America. Those who are caught and sent back to Mexico often return to try another day.

Although the Border Patrol monitors the border with everything from helicopters to movement sensors to night-vision goggles, many still slip past.