Found this little gem in Atlanta when we were looking for abandoned buildings. We were actually looking at the house in the next lot and met a nice couple who told us this building was in Stranger Things.
The secretive Hawkins National Laboratory is in fact the shuttered Georgia Mental Health Institute which is part of Emory University, a private university based in Atlanta. The exterior appears in the first shots in Season 1 where the building is established as belonging to the Ministry of Energy.
Photos copyright by Two Crafty Cats Photography