On the very day Iwo Jima was declared secured, Fifth Fleet Commander Admiral Raymond Spruance was on his flagship USS Indianapolis (CA-35) steaming to the Ryukyus in company with Admiral Marc Mitscher’s Task Force 58. In the following weeks, more than 1,600 ships and 350,000 naval personnel would assemble to form the largest amphibious assault force of World War II.  

On 1 April 1945, U.S. ground forces began the Battle of Okinawa. The objective was to secure the island, thus removing the last barrier standing between U.S. forces and Imperial Japan. With Okinawa firmly in hand, the U.S. military could finally bring its full might upon the Japanese, conducting unchecked strategic air strikes against the Japanese mainland, blockading its logistical lifeline, and establishing forward bases for the final invasion of Japan (Operation Olympic), scheduled for the fall of 1945.

The battle, which went into the month of June, was one of the most ferocious of the war with American casualties reaching a staggering 49,151, of which 12,520 were killed or missing. On an individual basis, 24 service members received the Medal of Honor for actions performed during the Battle of Okinawa. Thirteen went to the Marines and Navy corpsmen, nine to Army troops, and one to a Navy officer.

For more on the battle, read Battle of Okinawa: Historic Overview & Importance, an essay by NHHC historians Richard Hulver, Ph.D. and Martin R. Waldman, Ph.D. 

An infographic of the Battle of Okinawa, which for today's Navy, is a stark reminder of the importance of integrated American naval power, the necessity of conducting effective joint operations, and the value of being able to learn in real time.

Brave, Bold, and Fearless Firsts: The Wartime Experiences of Two Women at Iwo Jima and Okinawa. An infographic on Barbara Miller Finch and U.S. Navy flight nurse Ensign Jane "Candy" Kendeigh. 

Japanese propaganda leaflet recovered during the Battle of Okinawa.

• “The Most Difficult Antiaircraft Problem Yet Faced By the Fleet”: U.S. Navy vs. Kamikazes at Okinawa, historical essay by NHHC Historian Shawn R. Woodford
• “Closer Than Brothers”: The Loss of USS Twiggs at Okinawa, historical essay by NHHC Historian Guy Nasuti
• Investigating Okinawa: The Story Behind A Kamikaze Pilot’s Scarf, by NHHC Historian Richard Hulver, Ph.D. 
• "On the Verge of Breaking Down Completely": Combat Fatigue off Okinawa and the Destruction of USS Longshaw, historical essay by NHHC Historian Guy Nasuti.
• Admiral Spruance Recounts Kamikaze Attack on His Flagship, New Mexico (BB-40), a 13 May 1945 letter from Admiral Raymond Spruance to Captain Charles “Carl” J. Moore describing the second kamikaze attack he experienced at Okinawa, transcribed and edited by NHHC Historian Richard Hulver, Ph.D.
• A Ceremony for the Fallen: Aftermath of a Kamikaze Attack, historical essay by NHHC Historian Guy Nasuti
• The “Graveyard Shift”: The Most Dangerous Place off Okinawa, historical essay by NHHC Historian Guy Nasuti
• “Those Suicide Pilots Knew Where to Hit”: The Sinking of USS Little, historical essay by NHHC Historian Guy Nasuti
• “I Still Remember the Shipmates Who Didn’t Survive”: The Destruction of USS Pringle, historical essay by NHHC Historian Guy Nasuti
• "Like a Jockey Riding a Horse": Kamikaze Attack on USS Isherwood, historical essay by NHHC Historian Guy Nasuti
• A Kamikaze Attack on New Mexico, Fifth Fleet Flag: A Photo Essay, by NHHC Historian Richard Hulver, Ph.D.
• Okinawa Timeline: 4-11 April 1945
• Okinawa Timeline: 12-19 April 1945
• H-Gram 043-1: The Ship That Wouldn't Die--USS Franklin (CV-13), 19 March 1945 NHHC Director Sam Cox provides his thoughts on the ship and her heroic crew.
• Attack on Amphibious Assault Ship LSM(R)-188: A Lesson in Courage Blog by NHHC Historian Guy Nasuti.
• Navy Flight Surgeon on USS Franklin Recollections of LCDR Samuel Robert Sherman, MC, USNR, flight surgeon on USS Franklin (CV-13) when it was heavily damaged by a Japanese bomber near the Japanese mainland on 19 March 1945
• Action at Okinawa Synopsis of operation that focuses on the role of seaborne transport of personnel and supplies.
• Battle of Okinawa, 24 March–30 June 1945 Oral history from Commander Frederick Julian Becton onboard USS Laffey (DD-724).
• Navy Department Communiques and Pacific Fleet Communiques March 6, 1943–May 24, 1945. Chronological listing of events in the titles period.
• U.S. Navy Nurse in the Pacific Theater during World War II. Oral history from Capt. Ann Bernatitus recounting her service in the Philippines, evacuation from Corregidor and service during Okinawa campaign.
• From Dam Neck to Okinawa. Memoir of antiaircraft training in World War II.
• Donald W. Panek—World War II diary. Panek’s diary that records events related to invasion of Okinawa.
• Action Report, Battle of Okinawa at RP Station #1, 12 April 1945
• Action Report USS LCS (L) (3), Battle of Okinawa at RP Station, #1, April 12, 1945
• Radar Pickets and Methods of Combating Suicide Attacks off Okinawa Bulletin for combating kamikaze attacks.

• Okinawa Campaign April 1–June 21, 1945 & Okinawa Campaign: The Long Battle: April–June 1945 National Museum of the United States Navy photography exhibit on the Okinawa Campaign.
• Operation Iceberg—Okinawa Invasion in 1945. Photo essay on The Sextant, published 1 April 2015.