Bad Place architects design their neighborhoods at desks in a large open-plan office, and there are also rooms which can be booked for meetings. HQ also contains The Museum of Human Misery which includes an exhibit depicting Neighborhood 12358W and featuring animatronic representations of Eleanor, Chidi, Tahani and Jason. There is at least one portal (and likely more) leading to the Neutral Zone.
Shawn has a senior position at HQ, and Michael worked there before designing and moving into Neighborhood 12358W. Other characters who have been seen at Headquarters include Val, Toddrick Hemple and Glenn.
Chapter 24 takes place mainly within Bad Place Headquarters.