This is the order of battle for the US invasion of the island of Okinawa, the largest island of the Ryukyu chain. This offensive, called Operation Iceberg by its planners, was the final Allied offensive in the Pacific Theater of Operations in World War II.

The defending Japanese military was determined to inflict a casualty rate so high that the U.S. government would choose not to invade the Japanese home islands. To this end, the southern portion of Okinawa had been covered with the most extensive system of fortifications and interlocking fields of fire the Americans had yet encountered in the Pacific Theatre. In anticipation of this level of resistance, five full divisions, two Marine and three Army, were committed to the struggle.

The initial American landings took place on 1 April 1945 and the island was not declared secure until 22 June, a period of 82 days, far longer than was expected by US planners. Four days before the end of the campaign, Lieutenant General Simon Bolivar Buckner Jr. became the highest ranking U.S. military officer to be killed in action in the Second World War.

Summary of opposing ground forces

United States

US Tenth Army Lieutenant General Simon Bolivar Buckner Jr., USA () III Amphibious Corps Major General Roy S. Geiger, USMC Left: 6th Marine Division (24,356 officers and enlisted) Right: 1st Marine Division (26,274 officers and enlisted) XXIV Army Corps Major General John R. Hodge, USA Left: 7th Infantry ("Bayonet") Division (21,929 officers and enlisted) Right: 96th Infantry ("Deadeye") Division (22,330 officers and enlisted) Reserve: 27th Infantry ("New York") Division (16,143 officers and enlisted)

Japan

For most of the war, the Japanese had not considered Okinawa vital to their defensive arrangements. US progress in the Central Pacific led them to activate the Thirty-Second Army on the island in April 1944. In June, 5,000 men of the 44th Independent Mixed Brigade were lost at sea when their transport was torpedoed by a US submarine. The 9th Division, a veteran unit, was intended for Okinawa but was stranded on Formosa when the high command decided it couldn't risk more slow-moving transports in the East China Sea.Frank 1969, pp. 16-17 The unprecedented American casualty figures would almost certainly have been considerably higher had these men made it to Okinawa.

Japanese Thirty-Second Army Lieutenant General Mitsuru Ushijima () Approx. 67,000 men under arms, incl. 5,000 Okinawan conscriptsRottman 2004, p. 50 24th Division 62nd Division 44th Independent Mixed Brigade

American forces

US Tenth Army Lieutenant General Simon Bolivar Buckner Jr., USA () Major General Roy S. Geiger, USMC (18 Jun thru 23 Jun) General Joseph W. Stilwell, USA (from 23 Jun)

Northern Landing Area III Amphibious CorpsRottman 2004, pp. 55, 91-92 Major General Roy S. Geiger Chief of Staff: Brigadier General Merwin H. Silverthorn Chief of Corps Artillery: Brigadier General David R. Nimmer

Embarked in Task Force 53 under Rear Admiral Lawrence F. Reifsnider

Left Beaches 6th Marine Division Major General Lemuel C. Shepherd Jr. Asst. Div. Cmdr.: Brigadier General William T. Clement Chief of Staff: Colonel John C. McQueen G-1 (Personnel): Major Addison B. Overstreet G-2 (Intelligence): Lt. Colonel Thomas B. Williams G-3 (Operations): Lt. Colonel Victor H. Krulak G-4 (Logistics): Lt. Colonel August Larson (to 16 May), Lt. Colonel Wayne H. Adams

Left zone – Green beaches 22nd Marine Regiment Colonel Merlin F. Schneider (to 16 May), Colonel Harold C. Roberts (), Lt. Col. August Larson Exec. Ofc.: Colonel Karl K. Louther (to 16 May), Lt. Col. August Larson (to 17 Jun), Lt. Col. John B. Baker (to 20 Jun), Lt. Col. Samuel R. Shaw 1st Battalion (Major Thomas J. Myers (), Major Earl J. Cook (WIA 17 Jun), Lt. Col. Gavin C. Humphrey) CMoH recipients: Navy Corpsman Fred F. Lester () 2nd Battalion (Lt. Col. Horatio C. Woodhouse Jr. (), Lt. Col. John G. Johnson) CMoH recipients: Major Henry A. Courtney Jr. (), Cpl. James L. Day 3rd Battalion Lt. Col. Malcolm "O" Donohoo (WIA 16 May), Major George B. Kantner (to 19 May), Lt. Col. Clair W. Shisler)

Right zone – Red beaches 4th Marine Regiment Colonel Alan Shapley Exec. Ofc.: Lt. Col. Fred D. Beans (to 14 Apr), Lt. Col. Fred D. Beans (from 1 May) 1st Battalion (Major Bernard W. Green, Lt. Col. Fred D. Beans, Lt. Col. George B. Bell) CMoH recipient: Cpl. Richard Earl Bush 2nd Battalion (Lt. Col. Reynolds H. Hayden (to 26 May), Major Edgar F. Carney Jr.) 3rd Battalion (Lt. Col. Bruno A. Hochmuth)

Reserve – Landed D-Day 29th Marine Regiment Colonel Victor F. Bleasdale (to 14 Apr), Colonel William J. Whaling Exec. Ofc.: Lt. Col. Orin K. Pressley 1st Battalion (Lt. Col. Jean W. Moreau (WIA 16 May), Maj. Robert P. Neuffer (to 25 May), Lt. Col. Samuel S. Yeaton (to 14 Jun), Lt. Col. Leroy P. Hunt Jr.) 2nd Battalion (Lt. Col. William G. Robb (WIA 19 Apr)) 3rd Battalion (Lt. Col. Erma A. Wright (To 14 Jun), Lt. Col. Angus N. FraServ) CMoH recipient: Pvt. Robert M. McTureous Jr. ()

Artillery 15th Marine Regiment (Artillery) Colonel Robert B. Luckey Exec. Ofc.: Lt. Col. James H. Brower 1st Battalion (Major Robert H. Armstrong) 2nd Battalion (Major Nat M. Pace) 3rd Battalion (Lt. Col. Joe C. McHaney) 4th Battalion (Lt. Col. Bruce T. Henphill) CMoH recipient: PFC Harold Gonsalves ()

Service troops 6th Engineer Battalion (Maj. Paul F. Sackett) 6th Medical Battalion (Cmdr. John S. Cowan, USN) 6th Motor Transport Battalion (Lt. Col. Ernest H. Gould) 6th Pioneer Battalion (Lt. Col. Samuel R. Shaw (to 10 May), Maj. John G. Dibble (to 8 Jun), Lt. Col. Samuel R. Shaw (to 18 Jun), Maj. John G. Dibble) 6th Service Battalion (Lt. Col. George B. Bell (to 25 Apr), Lt. Col. Alexander N. Entringer) 6th Tank Battalion (Lt. Col. Robert L. Denig Jr.)

Right Beaches

1st Marine Division Major General Pedro A. del Valle Asst. Div. Cmdr.: Brigadier General Louis R. Jones Chief of Staff: Colonel Robert O. Bare G-1 (Personnel): Major Harold O. Deakin G-2 (Intelligence): Lt. Colonel John W. Scott Jr. G-3 (Operations): Lt. Colonel Russell E. Honsowetz G-4 (Logistics): Lt. Colonel Harvey C. Tschirgi

Left zone – Blue beaches 7th Marine Regiment Colonel Edward W. Snedeker Exec. Ofc.: Lt. Col. James M. Masters Sr. 1st Battalion (Lt. Col. John L. Gormley) 2nd Battalion (Lt. Col. Spencer S. Berger) 3rd Battalion (Lt. Col. Edward H. Hurst (WIA 19 Jun), Lt. Col. Stephen V. Sabol)

Right zone – Yellow beaches 5th Marine Regiment Colonel John H. Griebel Exec. Ofc.: Lt. Col. John D. Muncie 1st Battalion (Lt. Col. Charles W. Shelburne) CMoH recipient: PFC Albert E. Schwab () 2nd Battalion (Lt. Col. William B. Benedict (to 20 Jun), Major Richard T. Washburn) CMoH recipients: Navy Corpsman Robert Eugene Bush, Navy Corpsman William D. Halyburton Jr. () 3rd Battalion (Major John H. Gustafson (WIA 1 Apr), Lt. Col. John C. Miller, Jr. (4 Apr to 16 May), Major Frank W. Poland (to 8 Jun), Jr., Lt. Col. Robert B. Hill)

Reserve 1st Marine Regiment Colonel Kenneth B. Chappell (to 5 May), Colonel Arthur T. Mason Exec. Ofc.: Lt. Col. Richard P. Ross, Jr. (to 20 May), Lt. Col. James S. Monahan 1st Battalion (Lt. Col. James C. Murray, Jr. (WIA 9 May), Lt. Col. Richard P. Ross, Jr. (to 12 May), Lt. Col. Austin C. Shofner) CMoH recipients: Cpl. John P. Fardy (), Cpl. Louis J. Hauge Jr. () 2nd Battalion (Lt. Col. James C. Magee, Jr.) CMoH recipient: Pvt. Dale M. Hansen () 3rd Battalion (Lt. Col. Stephen V. Sabol (to 20 May), Lt. Col. Richard P. Ross Jr.) CMoH recipients: PFC William A. Foster (), Sgt. Elbert L. Kinser ()

Artillery 11th Marine Regiment (Artillery) Colonel Wilburt S. Brown Exec. Ofc.: Lt. Col. Edson L. Lyman 1st Battalion (Lt. Col. Richard W. Wallace) 2nd Battalion (Lt. Col. James H. Mofatt Jr.) 3rd Battalion (Lt. Col. Thomas G. Roe) 4th Battalion (Lt. Col. Leonard F. Chapman Jr.)

Service troops 1st Engineer Battalion (Major Theodore E. Drummond) 1st Medical Battalion (Lt. Cmdr. Francis Giuffrida, USN)) 1st Motor Transport Battalion (Lt. Col. Marion A. Fawcett (to 15 Apr), Lt. Col. Calvin C. Gaines) 1st Pioneer Battalion (Lt. Col. Robert G. Ballance) 1st Service Battalion (Lt. Col. Calvin C. Gaines (to 17 Apr), Col. John Kaluf) 1st Tank Battalion (Lt. Col. Arthur J. Stuart (WIA 13 Jun)) 3rd Armored Amphibian Battalion, Provisional (Lt. Col. John L. Williamson, Jr. (to 7 May), Major Arthur M. Parker, Jr.) 1st Amphibian Tractor Battalion (Lt. Col. Maynard M. Nohrden) 8th Amphibian Tractor Battalion (Lt. Col. Chalres B. Nerren (to 13 Apr), Major Bedford Williams (to 17 Apr), Lt. Col. Chalres B. Nerren)

1st Provisional Antiaircraft Artillery Group Colonel Kenneth W. Benner

Southern Landing Area XXIV Army CorpsRottman 2004, pp. 55, 90-91 Major General John R. Hodge

Embarked in Task Force 55 under Rear Admiral John L. Hall

Left Beaches

7th Infantry ("Bayonet") Division Major General Archibald V. Arnold Infantry 17th Infantry Regiment – Purple Beaches 32nd Infantry Regiment – Orange Beaches 184th Infantry Regiment – Reserve Artillery 48th, 49th, 57th Field Artillery Battalions (105mm) 31st Field Artillery Battalion (155mm) Division troops 7th Reconnaissance Troop (Mechanized) 13th Engineer Combat Battalion 7th Medical Battalion 7th Counter Intel Corps Det

Right Beaches

96th Infantry ("Deadeye") Division Major General James L. Bradley Infantry 381st Infantry Regiment – White Beaches CMoH recipient: Sgt. Beauford T. Anderson 382nd Infantry Regiment – Reserve CMoH recipients: PFC Clarence B. Craft, Lt. Seymour W. Terry 383rd Infantry Regiment – Brown Beaches CMoH recipient: PFC Edward J. Moskala () Artillery 361st, 362nd, 921st Field Artillery Battalions (105mm) 363rd Field Artillery Battalion (155mm) Division troops 96th Reconnaissance Troop (Mechanized) 321st Engineer Combat Battalion 321st Medical Battalion 96th Counter Intel Corps Det

Reserve – Landed L+8 27th Infantry ("New York") Division Major General George W. Griner Jr. Infantry 105th Infantry Regiment 106th Infantry Regiment 165th Infantry Regiment CMoH recipient: Sgt. Alejandro R. Ruiz Artillery 104th, 105th, 249th Field Artillery Battalions (105mm) 106th Field Artillery Battalion (155mm) Division troops 27th Reconnaissance Troop (Mechanized) 102nd Engineer Combat Battalion 102nd Medical Battalion 27th Counter Intel Corps Det

Western Islands (Ie Shima, etc.) Source:Rottman 2004, p. 91

77th Infantry ("Statue of Liberty") Division Major General Andrew D. Bruce

Embarked in Task Group 51.1 under Rear Admiral Ingolf N. Kiland

Infantry 305th Infantry Regiment – landed 17 Apr Red Beaches 1 & 2 CMoH recipients: Sgt. John W. Meagher, Sgt. Joseph E. Muller () 306th Infantry Regiment – landed 17 Apr Green Beach 307th Infantry Regiment – landed 17 Apr Red Beaches 3 & 4 CMoH recipients: Cpl. Desmond Doss, PFC Martin O. May () One Marine BLT Artillery 304th, 305th, 902nd Field Artillery Battalions (105mm) 306th Field Artillery Battalion (155mm) Division troops 77th Reconnaissance Troop (Mechanized) 302nd Engineer Combat Battalion 302nd Medical Battalion 77th Counter Intel Corps Det

Air Forces Tactical Air Force, Tenth Army Major General Francis P. Mulcahy, USMC (to 11 Jun) Major General Louis E. Woods, USMC (from 11 Jun)

Japanese forces

Thirty-Second Army Source:Rottman 2004, p. 93 Note:

Lieutenant General Mitsuru Ushijima () Approx. 67,000 men under arms, incl. 5,000 Okinawan conscriptsRottman 2004, p. 50 24th Division Lt. Gen. Tatsumi Amamiya () 22nd Infantry Regiment 32nd Infantry Regiment 89th Infantry Regiment 62nd Division Lt. Gen. Takeo Fujioka () 63rd Brigade 67th Brigade 44th Independent Mixed Brigade Maj. Gen. Suzuki Shigeji ()

Notes

References

Bibliography