On top of Philly news The City Commissioners set up 14 locations where you can cast your vote. One of the secure mail ballot drop boxes set up by Philadelphia's Office of City Commisioners Danya Henninger / Billy Penn �� Love Philly? Sign up for the free Billy Penn email newsletter to get everything you need to know about Philadelphia, every day. Philadelphia election officials postmarked the first batch of mail ballots for the May primary election, and voter drop boxes are open. The May 18 contest features a contested race for Philadelphia district attorney, as well as four questions about changes to the Pennsylvania Constitution.