The 3d Reconnaissance Troop was activated on August 20, 1940 at Fort Lewis, Washington in accordance with the Tables of Organization and Tables of Basic Allowances of a triangular division. Its cadre was supplied by the 4th Cavalry Regiment. Its Tables of Organization and Tables of Basic Allowances were changed frequently throughout peacetime training in an attempt to adapt it to the mission it was to execute. At different periods in the war it served as a specially organized task force in addition to its normal function.