1. United States Department of Defense
Defense Intelligence Agency (DIA)
National Security Agency (NSA)
National Reconnaissance Office (NRO)
National Geospatial-Intelligence Agency (NGA)
Service Agencies:
Army Military Intelligence (MI)
Office of Naval Intelligence (ONI)
Air Force Intelligence, Surveillance and Reconnaissance Agency (AF ISR or AIA)
Marine Corps Intelligence Activity (MCIA)

2. DIA
Established Mission - Provide timely, objective, and cogent military intelligence to war fighters, defense planners, and defense and national security policymakers.
HQ Pentagon,
Defense Intelligence Analysis Center, Bolling Air Force base
Defense Intelligence Medical Center, Ft. Detrick MD
Missile & Space Intelligence Center at Huntsville AL
Director of DIA is a three-star military officer who:
serves as principal adviser to the
Secretary of Defense and to the
Chairman of the Joint Chiefs of Staff
on matters of military intelligence.
Director also chairs the Military Intelligence Board, which coordinates activities of the defense intelligence community

3. DIA vs. CIA
The National Security Act of l947 had been purposely vague in defining CIA's responsibilities:
The Defense and State Departments opposed centralized management, arguing that to be prepared to conduct wartime operations they must exercise control over peacetime intelligence activities.
The result was essentially a compromise.
CIA became a "coordinator" in a confederation of departmental intelligence organizations.
Senior Military Intelligence Officers' Conference (SMIOC)
Defense Attaché System

4. National Security Agency (NSA)
the US government's cryptologic intelligence agency, administered under the U.S. Department of Defense.
Created on November 4, 1952, it is responsible for the collection and analysis of foreign communications and foreign signals intelligence, which involves a significant amount of cryptanalysis.
It is also responsible for protecting U.S. government communications and information systems from similar agencies elsewhere, which involves a significant amount of cryptography.

5. NSA
Contrary to popular impression, the NSA's work is limited to communications intelligence and not field or human intelligence activities.
By law, the NSA's intelligence gathering is limited to foreign communications;
surveillance within the U.S. is prohibited (FBI responsibility)
NSA is divided into two major missions:
the Signals Intelligence Directorate (SID), responsible for the production of foreign signals intelligence information, and
the Information Assurance Directorate (IAD), responsible for the protection of U.S. information systems

6. It’s eavesdropping mission includes radio broadcasting, both from various organizations and individuals, the Internet, telephone calls, and other intercepted forms of communication.
Its secure communications mission includes military, diplomatic, and all other sensitive, confidential or secret government communications.
NSA
Despite having been described as the world's largest single employer of mathematicians, and the owner of the single largest group of supercomputers, it has tried to keep a low profile 

7. National Reconnaissance Office (NRO)
NRO designs, builds & operates the reconnaissance satellites of the United States.
Coordinates collection and analysis of information from airplane and satellite reconnaissance by the military & CIA.
The agency is part of the Department of Defense.

8. NRO The NRO works closely with its “partners,” the:
National Security Agency (NSA),
National Geospatial-Intelligence Agency (NGA),
Central Intelligence Agency (CIA),
Defense Intelligence Agency (DIA),
United States Strategic Command, Naval Research Laboratory, and others
The NRO is responsible for operating Ground Stations around the world which collect and distribute intelligence gathered from reconnaissance satellites.

9. National Geospatial-Intelligence Agency
Primary mission is collection, analysis, and distribution of geospatial intelligence (GEOINT) in support of national security:
What is GEOspatial INTelligence ?
the exploitation and analysis of satellite information to describe, assess, and visually depict physical features and geographically referenced activities on the Earth.
GEOINT sources include imagery and mapping data, whether collected by commercial satellite, government satellite or by other means, such as Unmanned Aerial Vehicle (UAV) or recon aircraft.

10. Service Agencies: Army, Navy, Air Force, Marines
Army (MI): provide timely, relevant, accurate, and synchronized intelligence and electronic warfare support to tactical, operational and strategic-level commanders.
ONI was established to "seek out and report" on the advancements in other nations' navies.
Office of Naval Intelligence is the oldest continuously operating intelligence service in the United States.
Air Force Intelligence, Surveillance & Reconnaissance Agency organizes, trains, equips and presents assigned forces and capabilities to conduct intelligence, surveillance and reconnaissance for combat commanders.
Marine Corps Intelligence Activity (MCIA) provides tailored intelligence & services to the Marine Corps, based on expeditionary mission profiles in littoral areas.
MCIA determines what missions the Corps needs to carry out as well as who will need to be trained for that mission.