The Terrorist Identities Datamart Environment (TIDE) is the U.S. government's central database on known or suspected international terrorists, and contains highly classified information provided by members of the Intelligence Community such as CIA, DIA, FBI, NSA, and many others.
[1] In 2008, more than 27,000 names were removed from the list when it was determined they no longer met the criteria for inclusion.
[2] The Terrorist Identities Group (TIG), located in NCTC's Information Sharing & Knowledge Development Directorate (ISKD), is responsible for building and maintaining TIDE.
This database, in turn, is used to compile various watch lists such as the TSA's No Fly List, State Department's Consular Lookout and Support System, Homeland Security's Interagency Border Inspection System, and FBI's NCIC (National Crime Information Center) for state and local law enforcement.
The database is used by both the US and Canada, and applies to all borders, not just airports; it is provided, in addition to US personnel, to every Canadian border guard and immigration officer, who have the power to detain, interrogate, arrest and deny entry to anyone listed on it.