The Central Intelligence Agency (CIA) is an independent civilian intelligence agency of the United States government. It is an executive agency and reports directly to the Director of National Intelligence,^[7] with responsibility for providing national security intelligence assessment to senior United States policymakers. Intelligence-gathering is performed by non-military commissioned civilian intelligence agents, many of whom are trained to avoid tactical situations. The CIA also oversees and sometimes engages in tactical and covert activities at the request of the President of the United States.^[8] Often, when such field operations are organized, the U.S. military or other warfare tacticians carry these tactical operations out on behalf of the agency while the CIA oversees them.^[9] Although intelligence-gathering is the agency’s main agenda, tactical divisions were established in the agency to carry out emergency field operations that require immediate suppression or dismantling of a threat or weapon.^[10] The CIA’s headquarters is located in Langley, McLean, Fairfax County, Virginia,^[11] a few miles west of W

The CIA succeeded the Office of Strategic Services (OSS), formed during World War II to coordinate espionage activities against the Axis Powers for the branches of the United States Armed Forces. The National Security Act of 1947 established the CIA, affording it “no police or law enforcement functions, either at home or abroad”.^[12][13] Through interagency cooperation, the CIA has Cooperative Security Locations at its disposal. These locations are called “lily pads” by the Air Force.^[14][15] The primary function of the CIA is to collect information about foreign governments, corporations, and individuals, and to advise public policymakers, but it does conduct emergency tactical operations and carries out covert operations,^[16][17] and exerts foreign political influence through its tactical divisions, such as the Special Activities Division.^[18]ashington, D.C..

There has been considerable criticism of the CIA relating to: security and counterintelligence failures, failures in intelligence analysis, human rights concerns, external investigations and document releases, influencing public opinion and law enforcement, drug trafficking, and lying to Congress.^[19] Others, such as Eastern bloc defector Ion Mihai Pacepa, have defended the CIA as “by far the world’s best intelligence organization,” and argued that CIA activities are subjected to scrutiny unprecedented among the world’s intelligence agencies.^[20]

Source: http://en.wikipedia.org/wiki/Central_Intelligence_Agency