Former United States special operations units are disbanded or otherwise dormant unconventional warfare units of the United States military. Most units were created to fulfil categorical obligations within a particular conflict, and were disbanded once that conflict ended. All branches of the United States armed forces – the Army, Navy, Marine Corps and Air Force have fielded special operations units. For subsisting special operations units, see United States Special Operations Forces.

The Civil War

• Jessie Scouts, Union Army scout unit that operated disguised as Confederate States Army soldiers

World War II

• 1st Alaskan Combat Intelligence Platoon (Provisional) - "Castner's Cutthroats"
• 1st Special Service Force – "Devil's Brigade", a joint U.S.-Canadian unit
• 5307th Composite Unit (Provisional) – "Merrill's Marauders" – "Charles N. Hunter"
• Ranger Battalions
• Alamo Scouts
• Alaskan Scouts
• Marine Parachute Battalions – the "Paramarines"
• Marine Raider Battalions - the "Marine Raiders"
• United States Marine Corps Amphibious Reconnaissance Battalion, "VAC Amphib Recon Company" or "FMFPAC Amphib Recon Battalion"
• United States Marine Corps Scout (Tank) and Sniper Company – originated Scout Snipers and Division Recon
• Naval Scouts and Raiders
• Navy Combat Demolition Units (NCDU)
• US Navy Beach Jumpers
• Underwater Demolitions Teams (UDT) Precursor to the Navy SEALs
• 1st Air Commando Group
• Office of Strategic Services, whose functions included the arming, training and supplying of resistance movements; the use of propaganda, espionage, and subversion; and conducting post-war planning. Precursor to the CIA.

Korean War

• Airborne Ranger Companies (Korean War)
• Air Resupply And Communications Service (ARCS)
• Combined Command Reconnaissance Activities, Korea (CCRAK)
• Joint Advisory Commission, Korea (JACK) (Korean War), CIA-affiliated covert special operations unit
• United Nations Partisan Infantry Korea (UNPIK)

Vietnam War

• Fast Patrol Craft Patrol Craft Fast (PCF), also known as Swift Boats, were all-aluminum, 50-foot (15 m) long, shallow-draft vessels operated by the United States Navy for counterinsurgency (COIN) operations during the Vietnam War.
• Long Range Reconnaissance Patrols (LRRPs or "Lurps"); Vietnam War-era deep reconnaissance and raider units
• MIKE Force Mobile Strike Force Command; Corps I, II, III, IV
• Tiger Force (Vietnam War); reconnaissance commando (recondo) platoon in the 1/327th Infantry
• Project "Leaping Lena" (Vietnam War); Recondo course for South Vietnamese teams, trained by U.S. Special Forces, became Project DELTA.
• Project DELTA (Vietnam War); 5th Special Forces group long-range reconnaissance unit; precursor to MACV-SOG
• Military Assistance Command, Vietnam Studies and Observations Group (MACV-SOG), a joint covert Vietnam War-era task force composed of 2,000 American soldiers and over 8,000 indigenous mercenaries
• Project GAMMA/Project SIGMA MACV-SOG recon units that operated in Cambodia
• Project OMEGA Special Forces unit tasked to provide I Field Force Vietnam an SR capability in remote areas
• Phoenix Program; joint CIA and US military project based around the identification and elimination of the civilian supporters of the Viet Cong.
• Project 404/Palace Dog was a USAF program that supplied support personnel in civilian clothing to the Royal Laotian Air Force. Long range goal was production of a self-sufficient RLAF.
• Raven FACs were USAF pilots in civilian clothing assigned to support the Royal Laotian Air Force by directing air strikes from small aircraft.

Other

• 39th Special Forces Detachment (1952–1984), in Berlin, Germany, a classified unit that conducted unconventional warfare during the cold war
• 69th Special Forces Group (1963–1971), 8th Special Forces Group (1963–1972), 11th Special Forces Group (1961–1994) and 12th Special Forces Group (1961–1994) (disbanded Army Special Forces Groups)
• "Blue light", a counter-terrorist unit created among the 5th Special Forces Group in the late 1970s
• Special Operation - Reconnaissance, joint Marine-Navy reconnaissance units in the late 70s
• Task Force Bayonet, a Joint Task Force specialised in Foreign Internal Defense (FID) duties for Latin American countries; mainly composed of Special Forces, but also included United States Navy SEALs, Delta Force and Intelligence Support Activity operators
• US Army Special Operations Division
• SEASPRAY, an aviation unit for military covert operations during the 1980s
• Red Cell, U.S. "Tiger team" active in the 1980s
• Task Force Ranger (Operation Gothic Serpent), U.S Army Special Ops(75th Ranger Regiment, 3rd Ranger Battalion/ 160th SOAR/ Special Ops Detachment DELTA or Delta Force, now known as CAG)task force deployed to Somalia between August and October 1993
• Task Force 11 (Operation Enduring Freedom), joint Army/Navy task force created to capture or kill senior al-Qaeda and Taliban leaders in Afghanistan
• Task Force 20, Task Force 121 (Operation Iraqi Freedom), multinational joint task forces created to capture or kill senior leadership of the former Baathist regime in Iraq, including Saddam Hussein; also tasked with capturing or killing the leadership of the Iraqi insurgency as well as senior al-Qaeda operatives in Iraq; Task Force 20 later merged with Task Force 121, and is now believed to be active under the designation Task Force 77.
• Marine Corps Special Operations Command Detachment One (MCSOCOM-Det 1) (Operation Iraqi Freedom), pilot project active from 19 June 2003 to 10 March 2006 to assess the establishment of a permanent U.S. Marine Corps unit under Special Operations Command (SOCOM); replaced by the United States Marine Corps Forces Special Operations Command (MARSOC)
• Observer Group
• Marine Corps Test Unit#1