Tinian Naval Advanced Base was a major United States Navy sea and air base on Tinian Island, part of the Northern Mariana Islands on the east side of the Philippine Sea in the Pacific Ocean.

All construction was carried out by the Navy's Seabees 6th Naval Construction Brigade, including the main two airfields: West Field and North Field, serving the United States Army Air Forces's long-range Boeing B-29 Superfortress bombers.

Guam was seized by the United States in the Spanish-American War, and Spain sold the remaining islands to Germany.

[6] His staff, along with that of the US Army's 64th Engineer Topographic Battalion, drew up plans for the development of Tinian at Pearl Harbor in the months leading up to Operation Forager.

That day, the 121st commenced the rehabilitation of the 47,000-foot (14,000 m) airstrip in the north, filling in the bomb and shell craters.

[11] The 9th Troop Carrier Squadron was brought forward from Eniwetok, and its Douglas C-47 Skytrains, together with the Curtiss C-46 Commandos of VMR-252, delivered 33,000 rations from Saipan on 31 July.

[14] With the island declared secure, the seabees were released from the control of the V Amphibious Corps to the 6th Naval Construction Brigade, which became operational on 3 August.

Navy patrol planes commenced operations from the two North Field airstrips, but work to upgrade them to handle the B-29s could not be carried out while they were in use.

In addition to the runway, there were 16,000 feet (4,900 m) of taxiways, 70 hardstands, 345 Quonset huts, 33 repair and maintenance buildings, 7 magazines and a 75-foot (23 m) tall control tower.

The final runway, parallel to the other three, was assigned to the 135th Naval Construction Battalion and was completed on 5 May 1945, five days ahead of schedule.

Another complicating factor was the decision to have the B-29 taxi under their own power instead of being towed reduced the maximum taxiway grade from 2+1⁄2 to 1+1⁄2 percent, and required another 500,000 cubic yards (380,000 m3) of earth to be removed.

When work was completed on 5 May 1945, North Field had four parallel 8,500-foot (2,600 m) runways, 1,600 feet (490 m) apart, with 11 miles (18 km) of taxiways, 265 hardstands, 173 Quonset huts and 92 other buildings.

The beach work parties were relieved, and henceforth the three stevedore units handled all cargo.

[28][29] Early works on the harbor were carried out by the 50th and 92nd Naval Construction Battalions, which drove 200 feet (61 m) of piling that eventually formed part of the south bulkhead, and by the 107th Naval Construction battalion, which built a 1,150-foot (350 m) ramp from the shore to the reef.

In November 1944, the 50th Naval Construction Battalion commenced a major project to build permanent harbor facilities that could berth up to eight Liberty ships at a time.

A breakwater was built upon the existing reef consisting of 120 circular sheet piling cells that were 30 feet (9.1 m) in diameter and filled with coral.

[29] The Japanese roads on the island were too narrow for heavy construction vehicles, had inadequate drainage, and lacked shoulders.

Due to the shape of the island and the grid layout of its roads bearing a resemblance to those of Manhattan, the streets were named after those of New York City.

The 58th Bombardment Wing arrived from the China-Burma-India Theater in March 1945 and was based at West Field.

[42][43] A third formation, the 509th Composite Group, arrived in May 1945 and moved to the Columbia University district, south of 125th Street and adjacent to Riverside Drive, near the strips and hardstands of North Field, and took over the area that had been specially constructed for it.

[46] Altogether, 29,000 missions were flown by Tinian-based aircraft, and 157,000 short tons (142,000 t) of bombs were dropped.

[53] The military government was unprepared to cater for the large number of civilians, and there were critical shortages of relief supplies of all kinds.

The administrators responsible for public safety, education and labor had their offices inside the camp, and so were approachable.

The administrators met with each other at weekly staff meetings, ate their meals together in the common mess hall, and socialized at the officers' club, where African-American sailors waited on them.

[60] Rice and beans were staples, supplemented with canned meat, and fresh fish and vegetables.

Eighteen experienced Japanese teachers were found to revise and write texts, but were not permitted to teach.

[70] In late 1945, Admiral Raymond A. Spruance, the Commander-in-Chief, Pacific Ocean Areas (CINCPOA), ordered the repatriation of all Japanese and Korean civilians.

[73] The Navy disestablished the naval advanced base on Tinian on 1 December 1946,[74] but the United States military remained on the island.

As part of the lease in the 1980s, one runway at North Field was reactivated so U.S. Air Force Lockheed C-130 Hercules transports could support of U.S. Marine Corps training exercises.

[77] The U.S. Air Force's Rapid Engineer Deployable Heavy Operational Repair Squadron Engineers (RED HORSE) began clearing the overgrown old runways and access roads,[78] and on 11 April 2024, it was announced that Fluor Corporation had been awarded a $409 million contract to rebuild the airbase at North Field.