As of 2015, contact U.S. Immigration and Customs Enforcement at 866-347-2423 to report suspected illegal immigrants, according to the U.S. Department of Homeland Security. When calling, provide the person's name, work or residence location, and any other relevant information.
Alternatively, contact the border patrol sector in the area where the suspected illegal immigrant is located, advises the U.S. Department of Homeland Security. Find local contact information by hovering the mouse over the Border Security tab on the CBP.gov home page and clicking the Border Patrol Sectors link under the Along U.S. Borders heading on the left side of the drop-down menu. Find the closest sector, and select a station. Information provided for each station may include the station name, street address, mailing address, covered geographic location, and landline and fax telephone numbers.
Report suspected illegal activity involving illegal immigrants to U.S. Immigration and Customs Enforcement by clicking the How Do I link near the center of the ICE.gov home page, as indicated on the website. Next, select HSI TipLine under the For Law Enforcement heading. Call the telephone number provided, or click the Report Suspicious Criminal Activity link at the bottom of the page to email the information. Report activities such as human smuggling, employment and exploitation of unlawful workers, human trafficking, and human rights violations to the HSI Tipline.