The Battle of Peleliu, codenamed Operation Stalemate II by the United States, was fought between the United States and the Empire of Japan in the Pacific Theater of World War II, from September to November 1944 on the island of Peleliu (in present-day Palau). U.S. Marines of the First Marine Division, and later soldiers of the U.S. Army's 81st Infantry Division, fought to capture an airstrip on the small coral island. This battle was part of a larger offensive campaign known as Operation Forager, which ran from June to November 1944 in the Pacific Theater of Operations.
Major General William Rupertus, (USMC commander of 1st Marine Division) predicted the island would be secured within four days. However, because of Japan's well-crafted fortifications and stiff resistance, the battle lasted more than two months. In the United States, this was a controversial battle because of the island's questionable strategic value and the high casualty rate, which exceeded that of all other amphibious operations during the Pacific War. The National Museum of the Marine Corps called it "the bitterest battle of the war for the Marines".
Peleliu (or Beliliou) is an island in the island nation of Palau. Peleliu forms, along with two small islands to its northeast, one of the sixteen states of Palau. The island is noted as the location of the Battle of Peleliu in World War II.
Peleliu is approximately 10 kilometres (6.2 mi) northeast of the island of Angaur and 40 kilometres (25 mi) southwest of the island of Koror. Peleliu has a total area of 13 square kilometres (5.0 sq mi). As of 2000, its population was about 571, making it the third most populous state of Palau. Most of the island's population lives in the village of Kloulklubed which is the state capital on the northwestern coast. Including the capital, there are a total of four villages:
First sighting of Peleliu, Babeldaob, and Koror recorded by Westerners was by the Spanish expedition of Ruy López de Villalobos at the end of January of 1543. They were then charted as Los Arrecifes (“The Reefs” in Spanish). In November and December of 1710 these three islands were again visited and explored by the Spanish missionary expedition commanded by Sargento Mayor Francisco Padilla on board of the patache Santísima Trinidad. Two years later they were explored in detail by the expedition of Spanish naval officer Bernardo de Egoy. Following its defeat in the Spanish–American War, Spain sold Palau (including Peleliu) to Germany in 1899. Control passed to Japan in 1914.