Sheridan Penitentiary

Once home to 973 federal prisoners, now, just an empty building with work out equipment and locking gates, twenty miles outside of the city. In the final hours civilization a sympathetic prison guard unleashed them, and the ones who weren't infected fled into the surrounding foliage. Three stories, and 400 cells. The fences surrounding are electric, but someone would have to connect to the emergency generator to put them back in effect.