The United States Department of Homeland Security operates prescreening border control facilities at airports and other ports of departure located outside of the United States under agreement between it and the host country. Travelers are subject to immigration and customs inspections by Customs and Border Protection (CBP) officers before boarding their transportation onward to the United States. Preclearance applies to all passengers regardless of their nationality or purpose of travel. Upon arrival, precleared passengers arrive in the United States as domestic travelers, but may still be subject to re-inspection at the discretion of CBP. This process is intended to streamline border procedures, reduce congestion at American ports of entry, and facilitate travel into airports that otherwi