Tinian Island: The Base That Launched the Atomic Bombs

B-29s parked on Tinian during World War II. National Archives and Records Administration.

The island

Tinian, east of the Philippines and south of Japan, is part of the Commonwealth of the Northern Mariana Islands, administered by the United States; its residents are American citizens.

• Size: about 39 square miles (25,000 acres, 101 km²) — close to Los Alamos National Laboratory's 35 square miles, and about a tenth the size of Yellowstone.
• Shape: mostly flat; the highest point is 561 feet (171 m).
• People: 3,136 in 2010.

Before the war

• First settlers arrived about 1500 BCE; later migrants from the Caroline Islands and Southeast Asia joined them, and the resulting Indigenous people are the Chamorros.
• Spain held the island by the late 1600s, as a supply stop where Spanish, English, Dutch and French ships took on food and water. Disease and conflict cut the native population from around 100,000 to about 1400 by the 1700s, and in 1720 they were moved to Guam.
• Germany bought Tinian in 1899. Japan seized it in World War I and grew sugarcane, coffee and cotton, with more than 15,000 Japanese and Korean residents and very few Chamorros.

Battle and airbase

Late in World War II, Japan garrisoned Tinian, knowing it lay within bomber range of the home islands. The Allies attacked on July 24, 1944; the Battle of Tinian lasted to August 1.

• Japanese garrison: only 313 of 8500 men survived.
• Civilians: of 15,700, hundreds died in crossfire, were executed by Japanese troops, or killed themselves.
• Marines: more than 41,000 took part; 368 died and 1921 were wounded.

It was part of "island hopping," seizing bases from which to strike Japan. Navy Seabees at once began building the largest airbase of World War II — the largest airfield in the world at the time:

• a 40,000-person base with six runways of 8500 feet (2600 m), hardstands for hundreds of B-29s, and naval facilities including Tinian Harbor;
• laid out, because the island's shape recalled Manhattan, on New York's street pattern and names;
• home at one point to seven squadrons of the 58th Bombardment Wing, and a base for the Twentieth Air Force's 1945 raids: firebombing Japanese cities and Operation Starvation, which mined harbors and shipping lanes to cut off food imports.

The 509th Composite Group

Among the more than 500 aircraft using the runways were the specially modified "Silverplate" B-29s of the 509th Composite Group — secretly part of the Manhattan Project's Project Alberta, preparing to deliver atomic bombs. Almost none of its own men knew.

• Arrival: from their secret base at Wendover, Utah, in late April 1945, to their own separate base near North Field.
• Strength: by May, 225 officers and 1542 enlisted men, with their own quarters, rations, payroll and medical care, and an Air Engineering Squadron that could do depot-level repairs in the field, so no outsider ever needed to touch the secret planes.
• Support: five C-54 Skymasters, the "Green Hornet Line," for people and supplies, plus 51 scientists, military and security staff from Los Alamos and two officers from Washington.

Hiroshima and Nagasaki

• August 6, 1945, 2:30 a.m.: the Enola Gay left Tinian for Hiroshima carrying the uranium bomb Little Boy, with planes for instruments, photography and three for weather. Aboard were pilot Paul Tibbets, commander of the 509th, and Deak Parsons, mission commander, weaponeer and head of Project Alberta. The instrument plane carried Los Alamos physicists Luis Alvarez (a future Nobel laureate) and Harold Agnew (a future Los Alamos director).
• August 9: a strike force led by Charles Sweeny in Bockscar, with physicist Lawrence Johnston, carried the plutonium bomb Fat Man to Nagasaki.

Tinian today

• The runways: the planes went home after the war. All runways but one have decayed; the survivor, on West Field, serves Tinian International Airport. A military presence remains important to the economy; there were Marine exercises in the 1980s.
• Historic landmark: North Field is the heart of a National Historic Landmark District, with the bomber base and Japanese fortifications. The two bomb pits used to load the oversized bombs have been reopened under glass.
• Visitors come for beaches, scuba and snorkeling. Tinian is an Important Bird Area, home to the Tinian monarch, a reddish-brown flycatcher found only in the Marianas.
• Older history: Shinto shrines and latde (latte) stones — stone columns topped with half-spheres, once part of Chamorro buildings.

Sources

Based on "Tinian Island," Manhattan Project National Historical Park, National Park Service; a work of the United States government in the public domain. It cites Richard Rhodes, The Making of the Atomic Bomb, and James Kunetka, The General and the Genius (2015).