Reporting an illegal immigrant requires calling the Immigration and Customs Enforcement hotline, notes U.S. Customs and Border Protection. As of 2015, the phone number is 1-866-347-2423. A caller should have useful information available, including the immigrant's name, workplace or dwelling.
Another option is to contact the Border Patrol Sector in which the illegal aliens are currently located and request further investigation, notes U.S. Customs and Border Protection.
As of 2015, current immigration law mandates documentation of aliens for legal entry, notes the Federation for American Immigration Reform. The designation given to people who enter the country without documentation is EWI, which refers to having entered without inspection. Other illegal aliens have entered using accepted documentation but have then violated the provisions of entry by staying longer than their authorized period or taking types of work that were beyond their authorization. Immigration and Nationality Act Section 237 (a)(1)(B) indicates that any alien currently in the United States in violation of that law is subject to deportation.
As of 2012, 11.2 million unauthorized immigrants were present in the United States, or about 3.5 percent of the entire population, which was down from a peak of 12.2 million in 2007, notes Pew Research.