Phillydelphia
From My Little Wiki
Phillydelphia is an unseen city in Equestria and has been mentioned in My Little Pony: Friendship is Magic. During show development, Phillydelphia was proposed as the name for the home of the Mane Six before Ponyville was decided on. Princess Celestia had to visit Phillydelphia to help with their parasprite problem in FIM episode "Swarm of the Century".