US Customs and Border Protection Process

CAMPO, CA - MARCH 6: Mexican nationals who illegally crossed the California border are apprehended and handcuffed 3 miles inside US territory by Customs and Border Protection (CBP) agents on March 6, 2006 in Campo, California. The group had been running north through rough terrain without a guide and were near exhaustion. They wear woolen booties over their shoes to hide their tracks from CBP agents. Most Mexicans pay a smuggler 1300-1500 USD each to guide them across the border. Foot guides desert their groups if they sense CBP agents are nearby. Mexican nationals caught illegally crossing the border by CBP agents are sent back and classified as "voluntarily returned" without any charges if there is no outstanding criminal case on record. It is estimated that some 6.3 million illegal Mexican immigrants live in the US and some 485,000 undocumented Mexican immigrants enter the US annually. The US government estimates 11 million illegal immigrants reside in the US In 2005, San Diego and Imperial counties of southern California deported 40,335 Mexican and Central American immigrants. (Photo by Robert Nickelsberg/Getty Images)