Together these Sanctums generate a shield around the world.
The New York Sanctum is historically located at 177A Bleecker St, New York, as indicated by the placard on the exterior. However, the filming location for the Sanctum was done at 319 West 4th Street, on the 12th Street side of the building.
Strange steps out the W 12th St side of this building, looking East on 12th towards Greenwich Ave. Part of the exterior facade was a set piece while the rest of the front of the Sanctum is digitally created.
When the Sanctum shows up again in Avengers: Infinity War, it is located at it’s correct place in the city.
(Doctor Strange, 2016)