On February 19, 1945, men of the United States Marine Corps invaded the island of Iwo Jima, part of the Volcano Islands chain, in the North Pacific. This invasion, known as Operation Detachment, was a phase of the Pacific Theatre of World War II. The American goal was to establish multiple airfields that would allow escort fighters to accompany long-range bombers in their attacks on the Japanese home islands, as well as providing a place for damaged bombers to land on the return flight.

The Japanese military was determined to inflict a casualty rate so high that the U.S. government would give up its demand that Japan surrender unconditionally. To this end, the island had been covered with an extremely extensive system of fortifications and fields of fire. The United States Navy subjected the island to an unprecedented bombardment and, according to historian Samuel Eliot Morison, "In no previous operation in the Pacific had naval gunfire support been so effective as at Iwo Jima."Morison, p. 40 Nonetheless, Japanese artillery and machine-gun fire were extremely effective because the underground bunkers were so strong, only a direct hit by a bomb or naval shell could knock one out. Since direct hits were very difficult on well-camouflaged bunkers, many survived and inflicted a huge casualty rate on the Marines.

For the conquest of Iwo Jima, the Marine Corps assigned three divisions, a total of almost 70,000 troops, in stark contrast to the single division tasked with capturing Guadalcanal in August 1942. The conquest of Iwo Jima took five weeks, far beyond the American estimates.

United States

Naval forces United States Pacific Fleet Admiral Chester W. Nimitz HQ at Pearl Harbor United States Fifth Fleet Admiral Raymond A. Spruance in heavy cruiser Indianapolis Joint Expeditionary Force (Task Force 51) Vice Admiral Richmond Kelly Turner in amphibious command ship Eldorado Amphibious Support Force (Task Force 52) Rear Admiral William H.P. Blandy in amphibious command ship Estes Attack Force (Task Force 53) Rear Admiral Harry W. Hill in amphibious command ship Auburn Fast Carrier Task Force (Task Force 58) Rear Admiral Marc Mitscher in aircraft carrier Lexington

Ground forces

Expeditionary Troops (Task Force 56) Lieutenant General Holland Smith Chief of Staff: Col. Dudley S. Brown Personnel officer (G-1): Col. Russell N. Jordahl Intelligence officer (G-2): Col. Edmond J. Buckley Operations officer (G-3): Col. Kenneth H. Weir Logistics officer (G-4): Col. George R. Rowan

V Amphibious Corps Major General Harry Schmidt Chief of Staff: Brig. Gen. William W. Rogers Personnel officer (G-1): Col. David A. Stafford Intelligence officer (G-2): Col. Thomas R. Yancey Operations officer (G-3): Col. Edward A. Craig Logistics officer (G-4): Col. William F. Brown 8th Marine Field Depot (shore party command): Col. Leland S. Swindler Landing Force Air Support Control Unit 1: Col. Vernon E. Megee 62nd Seabees

Left landing area (Green and Red Beaches): 5th Marine Division (25,884 officers and enlisted) Major General Keller E. Rockey Asst. Div. Cmdr.: Brig. Gen. Leo D. Hermle Chief of Staff: Col. Ray A. Robinson CO HQ Battalion: Maj. John Ayrault, Jr. Personnel officer (G-1): Col. John W. Beckett Intelligence officer (G-2): Lt. Col. George A. Roll Operations officer (G-3): Col. James F. Shaw, Jr. Logistics officer (G-4): Col. Earl S. Piper Plans officer (G-5): Lt. Col. Frederick H. Dowsett

Green Beach: 28th Marine Regiment Colonel Harry B. "Harry the Horse" Liversedge Exec. Ofc.: Lt. Col. Robert H. Williams 1st Battalion (Lt. Col. Jackson B. Butterfield) CMoH recipients: Cpl. Tony Stein (), Sgt. William G. Harrell 2nd Battalion (Lt. Col. Chandler W. Johnson (), Maj. Thomas B. Pearce, Jr.) CMoH recipients: PFC Donald J. Ruhl (), Pvt. George Phillips () 3rd Battalion (Lt. Col. Charles E. Shepard, Jr. (to 14 Mar), Maj. Tolson A. Smoak (to 25 Mar), Lt. Col. Shepard) CMoH recipient: Navy Corpsman Jack Williams ()

Red Beaches 1 & 2: 27th Marine Regiment Colonel Thomas A. Wornham Exec. Ofc.: Col. Louis C. Plain (WIA 19 Feb), Lt. Col. James P. Berkeley) 1st Battalion (Lt. Col. John A. Butler (), Lt. Col. Justin C. Duryea (WIA 9 Mar), Lt. Col. William H. Tumbleston (WIA 14 Mar) CMoH recipient: Sgt. Joseph R. Julian () 2nd Battalion (Maj. John W. Antonelli (WIA 9 Mar), Maj. Gerald F. Russell) CMoH recipient: Lt. Jack Lummus () 3rd Battalion (Lt. Col. Donn J. Robertson) CMoH recipients: Sgt. William G. Walsh (), Navy Corpsman John H. Willis () Reserve: 26th Marine Regiment Colonel Chester B. Graham Exec. Ofc.: Col. Lester S. Hamel 1st Battalion (Lt. Col. Daniel C. Pollock (WIA 19 Mar), Maj. Albert V.K. Gary) CMoH recipients: Cpl. Charles J. Berry (), Capt. Robert Hugo Dunlap, PFC Jacklyn Harrell Lucas 2nd Battalion (Lt. Col. Joseph P. Sayers (WIA 23 Feb), Maj. Amadeo Rea) CMoH recipients: Pvt. Franklin E. Sigler, Navy Corpsman George E. Wahlen 3rd Battalion (Lt. Col. Tom M. Trotti (), Maj. Richard Fagan) CMoH recipient: PFC William R. Caddy ()

13th Marine Regiment (Artillery) Colonel James D. Waller 1st Battalion (Lt. Col. John S. Oldfield) 2nd Battalion (Maj. Carl W. Hjerpe) 3rd Battalion (Lt. Col. Henry T. Waller) 4th Battalion (Maj. James F. Coady)

Service troops Colonel Benjamin W. Gaily 3rd Amphibian Tractor Battalion (Lt. Col. Sylvester L. Stephan) 11th Amphibian Tractor Battalion (Lt. Col. Albert J. Roose) 5th Engineer Battalion (Lt. Col. Clifford H. Shuey) 5th Medical Battalion (Lt. Cmdr. William W. Ayres, USN) 5th Motor Transport Battalion (Maj. Arthur F. Torgler, Jr.) 5th Pioneer Battalion (Maj. Robert S. Riddell) 31st Naval Construction Battalion CMoH recipient: Lt. Harry L. Martin () 5th Service Battalion (Maj. Francis P. Daly (), Maj. Gardelle Lewis (from 26 Feb)) 5th Tank Battalion (Lt. Col. William R. Collins)

Right landing area (Yellow and Blue beaches): 4th Marine Division (24,452 officers and enlisted) Major General Clifton B. Cates Asst. Div. Cmdr.: Brig. Gen. Franklin A. Hart Chief of Staff: Col. Merton J. Batchelder CO HQ Battalion: Col. Bertrand T. Fay Personnel officer (G-1): Col. Orin H. Wheeler Intelligence officer (G-2): Lt. Col. Gooderham L. McCormick Operations officer (G-3): Col. Edwin A. Pollock Logistics officer (G-4): Col. Matthew C. Horner

Yellow Beaches 1 & 2: 23rd Marine Regiment Colonel Walter W. Wensinger Exec. Ofc.: Lt. Col. Edward J. Dillon 1st Battalion (Lt. Col. Ralph Haas (), Lt. Col. Louis B. Blissard) CMoH recipient: Sgt. Darrell S. Cole () 2nd Battalion (Maj. Robert H. Davidson) CMoH recipient: PFC Douglas T. Jacobson 3rd Battalion (Maj. James S. Scales) CMoH recipient: Lt. Col. Justice M. Chambers

Blue Beach 1: 25th Marine Regiment Colonel John R. Lanigan Exec. Ofc.: Lt. Col. Clarence J. O'Donnell 1st Battalion (Lt. Col. Hollis U. Mustain (), Maj. Fenton J. Mee) CMoH recipient: Sgt. Ross F. Gray () 2nd Battalion (Lt. Col. Lewis C. Hudson, Jr. (WIA 20 Feb), Lt. Col. James Taul) 3rd Battalion (Lt. Col. Justice M. Chambers (WIA 22 Feb), Capt. James C. Headley)

Reserve: 24th Marine Regiment Colonel Walter I. Jordan Exec. Ofc.: Lt. Col. Austin R. Brunelli 1st Battalion (Maj. Paul S. Treitel (to 8 Mar), Lt. Col. Austin R. Brunelli) 2nd Battalion (Lt. Col. Richard Rothwell) CMoH recipients: Capt. Joseph J. McCarthy, Navy Corpsman Francis J. Pierce

14th Marine Regiment (Artillery) Colonel Louis O. DeHaven Exec. Ofc.: Lt. Col. Randall M. Victory 1st Battalion (Maj. John B. Edgar, Jr.) 2nd Battalion (Maj. Clifford B. Drake) 3rd Battalion (Lt. Col. Robert E. MacFarlane (), ) 4th Battalion (Lt. Col. Carl A. Youngdale ())

Service troops Lt. Colonel Melvin L. Krulewitch 5th Amphibian Tractor Battalion (Maj. George L. Shead) 10th Amphibian Tractor Battalion (Maj. Victor J. Croizat) 4th Engineer Battalion (Lt. Col. Nelson K. Brown) 4th Medical Battalion (Cmdr. Reuben L. Sharp, USN) 4th Motor Transport Battalion (Lt. Col. Ralph L. Schiesswohl) 4th Pioneer Battalion (Lt. Col. Richard G. Ruby) 133rd Naval Construction Battalion 4th Service Battalion (Lt. Col. John F. Fondahl) 4th Tank Battalion (Lt. Col. Richard K. Schmidt)

Floating reserve: 3rd Marine Division (19,597 officers and enlisted) Major General Graves B. Erskine Asst. Div. Cmdr.: Brig. Gen. William A. Worton Chief of Staff: Col. Robert E. Hogaboom CO HQ Battalion: Lt. Col. Jack F. Warner (to 14 Mar), Lt. Col. Carey A. Randall Personnel officer (G-1): Maj. Irving R. Kriendler Intelligence officer (G-2): Lt. Col. Howard J. Turton Operations officer (G-3): Col. Arthur H. Butler Logistics officer (G-4): Col. James D. Hittle

Committed to center sector D+2, attached to 4th Marine Division: 21st Marine Regiment Colonel Hartnoll J. Withers Exec. Ofc.: Lt. Col. Eustace R. Smoak 1st Battalion (Lt. Col. Marlowe C. Williams (WIA 22 Feb), Maj. Clay M. Murray (WIA 22 Feb), Maj. Robert H. Houser) CMoH recipient: Cpl. Hershel W. Williams 2nd Battalion (Lt. Col. Lowell E. English (WIA 2 Mar), Maj. George A. Percy) 3rd Battalion (Lt. Col. Wendell H. Duplantis)

Committed D+6: 9th Marine Regiment Colonel Howard N. Kenyon Exec. Ofc.: Lt. Col. Paul W. Russell 1st Battalion (Lt. Col. Carey A. Randall (to 6 Mar), Maj. William T. Glass (to 14 Mar), Lt. Col. Jack F. Warner) CMoH recipient: Lt. John H. Leims 2nd Battalion (Lt. Col. Robert E. Cushman, Jr.) CMoH recipient: Pvt. Wilson D. Watson 3rd Battalion (Lt. Col. Harold C. Boehm)

12th Marine Regiment (Artillery) Lieutenant Colonel Raymond F. Crist Jr. Exec. Ofc.: Lt. Col. Bernard H. Kirk 1st Battalion (Maj. George B. Thomas) 2nd Battalion (Lt. Col. William T. Fairbourn) 3rd Battalion (Lt. Col. Alpha L. Bowser, Jr.) 4th Battalion (Maj. Joe B. Wallen (to 20 Mar), Lt. Col. Thomas R. Belzer)

Arrived on March 20 and attached to 3rd Marine DivisionArmy Boots on Volcanic Sands: The 147th Infantry Regiment at Iwo Jima (https://www.jstor.org/stable/26300958) 147th Infantry Regiment (Ohio Army National Guard) Colonel Robert F. Johnson Exec. Ofc.: Lt. Col. Eustace R. Smoak 1st Battalion 2nd Battalion 3rd Battalion

Service troops Colonel James O. Brauer (to 6 Mar), Colonel Lewis A. Hohn 3rd Engineer Battalion (Lt. Col. Nelson K. Brown) 3rd Medical Battalion (Cmdr. Reuben L. Sharp, USN) 3rd Motor Transport Battalion (Lt. Col. Ralph L. Schiesswohl) 3rd Pioneer Battalion (Lt. Col. Richard G. Ruby) 3rd Tank Battalion (Lt. Col. Richard K. Schmidt)

Never landed: 3rd Marine Regiment Colonel James A. Stuart

Japan

Lieut. General Tadamichi Kuribayashi, commanding Colonel Tadashi Takaishi, chief of staff 21,060 total men under arms Army Lieutenant General Tadamichi Kuribayashi 109th Infantry Division 145th Infantry Regiment 17th Mixed Infantry Regiment 26th Tank Regiment 2nd Mixed Brigade Navy Rear Admiral Rinosuke Ichimaru 125th Anti-Aircraft Defense Unit 132nd Anti-Aircraft Defense Unit 141st Anti-Aircraft Defense Unit 149th Anti-Aircraft Defense Unit

See also Orders of battle involving United States Marine forces in the Pacific Theatre of World War II:

Battle of Guadalcanal order of battle Battle of Tarawa opposing forces Battle of Saipan order of battle Guam (1944) order of battle Battle of Leyte opposing forces Battle of Peleliu opposing forces Okinawa ground order of battle

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