"The concept of a U.S. Intelligence Community (IC) of integrated component departments and agencies began to take shape after World War II, in part through the establishment of the Central Intelligence Agency. Prior to that time, U.S. intelligence organizations existed within the military services and largely operated independently of one another. References to an Intelligence Community first appear in the mid-1950s. The components of the IC were first specified in statute by the Intelligence Organization Act of 1992 (Title VII of P.L. 102-496). The IC has since evolved into a federated community of 17 components spread across 2 independent agencies and 6 separate departments of the federal government."
CRS In Focus, IF10527