Main Core is the code name of an American governmental database that is believed to have been in existence since the 1980s. It is believed that Main Core is a federal database containing personal and financial data of millions of United States citizens believed to be threats to national security. The data which is believed to come from the NSA, FBI, CIA, and other sources, is collected and stored without warrants or court orders. The database's name derives from the fact that it contains "copies of the 'main core' or essence of each item of intelligence information on Americans produced by the FBI and the other agencies of the U.S. intelligence community".
The Main Core database is alleged to have originated with the Federal Emergency Management Agency (FEMA) in 1982, following Ronald Reagan's Continuity of Operations plan outlined in the National Security Directive (NSD) 69 / National Security Decision Directive (NSDD) 55, entitled "Enduring National Leadership", implemented on September 14, 1982.
As of 2008, there were allegedly eight million Americans listed in the database as possible threats, often for trivial reasons, whom the government may choose to track, question, or detain in a time of crisis.
The existence of the database was first asserted in May 2008 by Christopher Ketcham and in July 2008 by Tim Shorrock.