United States Post Office, Courthouse, and Federal Office Building, Federal courthouse in downtown Oklahoma City, United States.

The United States Post Office, Courthouse, and Federal Office Building is a three-story limestone building designed by the Office of the Supervising Architect under James Knox Taylor and completed in 1912. Its Beaux-Arts Classicism shows in the symmetry, balustrade, pilasters, pediments, arched openings and shallow balconies, under a red-tile roof. Two western additions, in 1919 and 1932, doubled and then extended it; the 1932 work added a central tower with Art Deco motifs.

The building was constructed in 1912 and marked the beginning of governmental development in Oklahoma just five years after territorial statehood was achieved. Its establishment reflected the rapid institutional expansion occurring during this early period of the state.

The building's name recalls its original role as a post office, which moved out in 1966 while the courts stayed. Since 2015 the Federal Judicial Learning Center & Museum has occupied part of the restored first-floor lobby, presenting the judicial history of the Western District of Oklahoma through the Historical Society founded in 2010.

The building occupies a full block of downtown Oklahoma City, with the main entrance on the south side facing Dean A. McGee Avenue. It still operates as a working federal courthouse, holding the Bankruptcy Court for the Western District of Oklahoma, so expect courthouse security screening at the doors. The Federal Judicial Learning Center & Museum sits in the restored first-floor lobby.

The 1933 trial of George "Machine Gun" Kelly for kidnapping oilman Charles F. Urschel was the first in the nation to admit sound and picture equipment into a federal courtroom. Kelly received a life sentence and was sent to Alcatraz.