Activity over time
Events per year
| Date | Event | Lanes | Status |
|---|
| 1952-11-04 | Truman Creates National Security Agency by Classified Directive, Existence Classified for 23 Years
3 src Harry S. Truman · National Security Agency · Armed Forces Security Agency |
| confirmed |
| 1947-12-19 | NSC 4-A Secretly Authorizes CIA Covert Action Using "Fifth Function" Elastic Clause of 1947 Act
3 src Harry S. Truman · National Security Council · Central Intelligence Agency | | confirmed |
| 1947-09-18 | Central Intelligence Agency Begins Operations Under 1947 National Security Act
3 src Harry S. Truman · Central Intelligence Agency · Allen Dulles | | confirmed |
| 1943-02-01 | Army Signal Intelligence Service Begins VENONA Soviet Cable Decryption, Foundation for Post-War Counterintelligence
3 src Federal Bureau of Investigation · National Security Agency | | confirmed |
| 1936-08-24 | Roosevelt Secret Oral Directive Authorizes FBI General Intelligence Without Statutory Basis
3 src Franklin D. Roosevelt · J. Edgar Hoover · Federal Bureau of Investigation | | confirmed |
| 1935-07-01 | Bureau of Investigation Formally Renamed Federal Bureau of Investigation, Professionalization Era Begins
2 src J. Edgar Hoover · Federal Bureau of Investigation · Franklin D. Roosevelt · Homer Cummings | | confirmed |
| 1930-04-30 | Army Signal Intelligence Service Founded Under Friedman, Institutional Ancestor of NSA
3 src | | confirmed |
| 1929-10-31 | Stimson Closes Yardley's Black Chamber, Briefly Interrupting U.S. Peacetime Signals Intelligence
3 src State Department | | confirmed |
| 1924-05-10 | Hoover Named Acting Director of Bureau of Investigation, Begins 48-Year Tenure
3 src J. Edgar Hoover · Harlan Fiske Stone · Bureau of Investigation · Calvin Coolidge |
| confirmed |
| 1917-01-16 | British Intercept Zimmermann Telegram, Demonstrating Value of Signals Intelligence to U.S. Policy
2 src Woodrow Wilson | | confirmed |
| 1916-07-30 | German Sabotage Destroys Black Tom Munitions Depot, Exposes U.S. Counterintelligence Vacuum
2 src Bureau of Investigation | | confirmed |
| 1908-07-26 | Bonaparte Creates Bureau of Investigation Inside DOJ, Bypassing Congressional Opposition
3 src Theodore Roosevelt · Department of Justice · Bureau of Investigation | | confirmed |
| 1861-04-21 | Pinkerton Heads Union Intelligence Service for McClellan, First Federal Use of Private Intelligence Personnel
2 src Allan Pinkerton · Pinkerton National Detective Agency · Abraham Lincoln | | confirmed |
| 1850-08-22 | Allan Pinkerton Founds North-Western Police Agency, Precursor to Private Intelligence State
2 src Allan Pinkerton · Pinkerton National Detective Agency |
| confirmed |