The Mt. Megantic International Dark Sky Reserve covers an area of almost 5,500 km2. It is centered on the Observatory within the provincial park and has a radius of 50 km. The Reserve also includes the City of Sherbrooke, 60 km away. These zones were based on calculations that identified the various sources of light pollution at the summit of Mt. Megantic.
A sign has been placed at the foot of the mountain, soon to be followed by others in the region, to inform tourists that they are passing through an International Dark Sky Reserve.