St Mungo's occupies a former Muggle department store, Purge and Dowse, Ltd., in the heart of Muggle London. The location was chosen after it became apparent that no building in Diagon Alley would large enough to accommodate all the various wards. The location of the hospital allows patients to exit onto a crowded street and blend in seamlessly with the Muggles, therefore avoiding discovery by Muggles. The entrance to St. Mungo’s works similarly to that of Diagon Alley, where those wishing to enter the hospital must talk to a mannequin located inside the now dilapidated department store.
Security at the hospital is tight, and once someone enters they are evaluated to determine if they pose any threat. The interior of the hospital looks much like any other, with sterile white walls and uncomfortable waiting areas. The main entrance opens to a reception and triage area, where all new patients and visitors must check in. The hospital is spread out over six floors, each catering to a specific type of ailment or injury.
The uniform of St Mungo's Healers includes a lime green robe which bears the hospitals insignia on the chest. There are five wards, each of which is dedicated to the treatment of a specific type of magical malady or injury.
Ground Floor - Artefact Accidents:
This ward deals with injuries caused by exploding cauldrons, backfiring wands, cursed objects, or anything that results from the use of a magical item.
First Floor - Creature-Induced Injuries:
This ward deals with bites, burns, and other injuries caused by magical creatures. Victims of werewolf attacks are treated in this ward.
Second Floor - Magical Bugs and Diseases:
This ward cares for those suffering from magical illnesses such as dragon pox and vanishing sickness. The majority of patients in this ward are children.
Third Floor - Potions and Plant Poisoning:
This ward deals with injuries and side-effects from exposure to dangerous plants and potions. Due to the danger of posed by certain magical plants, this ward has an extra level of security to ensure that no dangerous plants are allowed out of the ward and to prevent contagious rashes from spreading to other wards.
Fourth Floor - Spell Damage:
This ward deals with injuries caused by spells cast at the victim. This floor also includes the Janus Thickey Ward, a highly secure ward with long-term residents who are no longer capable of caring for themselves and pose a danger to others due to spell damage.
Sixth Floor - Tea Room and Gift Shop:
The tea room and gift shop are open to patients, visitors, and staff. They offer a relaxing place to mingle and rest while at the hospital.