The Major-General George R. Pearkes Building (often abbreviated as just Pearkes) is the principal location of Canada's National Defence Headquarters (NDHQ) and is located in downtown Ottawa, Ontario.
NDHQ actually comprises a collection of offices spread across the National Capital Region, however it is most commonly identified with the Major-General George R. Pearkes Building at 101 Colonel By Drive in Ottawa.
The building and the adjacent Rideau Centre are both served by OC Transpo's Mackenzie King Transitway station.
The building, named after Major-General G.R. Pearkes, was constructed between 1969 and 1974, and was originally intended for use by the Department of Transport. When a planned National Defence Headquarters complex on the LeBreton Flats was not built, however, DND acquired the Colonel By Drive structure. In 1972, the Department of Transportation moved into Place de Ville's newly completed Tower C.
The concept for the building (actually a group of buildings) was developed by French town planner Jacques Gréber immediately after World War II at the invitation of Prime Minister William Lyon Mackenzie King. Gréber, a proponent of boulevards and highways as opposed to rail corridors, advised that the city redevelop the east bank of the Rideau Canal which was, at that time, covered with railway tracks leading to Ottawa Union Station.