The Battle of Okinawa , codenamed Operation Iceberg, was a major battle of the Pacific War fought on the island of Okinawa by United States Army and United States Marine Corps forces against the Imperial Japanese Army. The initial invasion of Okinawa on 1 April 1945 was the largest amphibious assault in the Pacific Theater of World War II. The Kerama Islands surrounding Okinawa were preemptively captured on 26 March by the 77th Infantry Division. The 82-day battle lasted from 1 April until 22 June 1945. After a long campaign of island hopping, the Allies were planning to use Kadena Air Base on the large island of Okinawa as a base for Operation Downfall, the planned invasion of the Japanese home islands, 340 mi (550 km) away.

Okinawa Island , officially Okinawa Main Island , is the largest of the Okinawa Islands and the Ryukyu (Nansei) Islands of Japan in the Kyushu region. It is the smallest and least populated of the five main islands of Japan. The island is approximately 106 kilometres (66 mi) long, an average 11 kilometres (7 mi) wide, and has an area of 1,206.98 square kilometers (466.02 sq mi). It is roughly 640 kilometres south of the main island of Kyushu and the rest of Japan. It is 500 km northeast of Taiwan. The total population of Okinawa Island is 1,384,762. The greater Naha area has roughly 800,000 residents, while the city itself has about 320,000 people. Naha is the seat of Okinawa Prefecture on the southwestern part of Okinawa Island. Okinawa has a humid subtropical climate.