The No. 2 US Air Command Operations and Signals Building, constructed of reinforced concrete with a buttressed external blast wall, was constructed in early 1942. It functioned as a strategic communications centre for the US Army’s No.2 Air Command in north eastern Australia and New Guinea, continued to be occupied by US Army signals units throughout the war and was also used for aircraft bomb sight repair. The building was derelict after the war until being adapted as an office during the 1960s. It is located north of Ingham Road and east of Ramsay Street, and is roughly half way between Castle Hill and Garbutt Airport.

The original building has a central corridor running roughly east-west lengthways, with rooms opening off the corridor. The eastern end contains a large sunken room accessed by several steps. The building retains its original layout with only minor alterations, including the removal of the original mechanical ventilation system. A rectangular projecting room at the western end of the building originally contained the bomb site repair facilities. An added upper floor covers most of the original building, and a later extension has been added to the west. Several sections of the buttressed external blast wall have been removed to allow greater access.