Commander in Chief Pacific Fleet Headquarters, Military headquarters at Pearl Harbor-Hickam Joint Base, United States.

Commander in Chief Pacific Fleet Headquarters is a three-story reinforced concrete structure about 60 by 200 feet, set on the north side of Makalapa Drive above the lower reaches of Halawa Stream. Its upper floors are ringed by lanais, so the building needs no indoor corridors, and the lower floor, built as a basement, was bombproof by design in 1942.

Built in the 1940s, the building served as the command center where Admiral Chester Nimitz coordinated naval operations across the entire Pacific Ocean during World War II. From this location, Nimitz oversaw major naval battles from Midway to the Mariana Islands.

The building's name, CINCPAC, abbreviates Commander in Chief, Pacific Fleet, the title Admiral Chester W. Nimitz held there from 1942 to 1945. Its upper floors are ringed by lanais, open porches that replace indoor corridors, a feature of Hawaiian military architecture. The Navy's wartime plan for Makalapa included two nearby buildings for intelligence and communications.

The building stands on the north side of Makalapa Drive, overlooking the lower reaches of Halawa Stream, in the section of Joint Base Pearl Harbor-Hickam between Interstate H1 and Kamehameha Highway. It is an active military facility, so access and viewing may be limited.

The building received National Historic Landmark status in 1987 for its critical role in coordinating naval operations across the entire Pacific region during the war. This recognition honors its importance to military strategy across one of history's largest campaigns.