My dictionary, for when the Urban Dictionary doesn't have it or gets it wrong.

Filthadelphia   A once-great city in Pennsylvania, once home to Benjamin Franklin and host to the Second Continental Congress, this city is now a blue cesspool, with a massive parasite population and multiple murders on many days. With a parasite population of over a half million, it is listed as a category 2A target on the MacArthur index. Also referred to as Filthydelphia or Killadelphia (the latter due to the incessant murdering).