Philadelphia Union | 21,679 followers on LinkedIn. Philadelphia Union is an American professional soccer club based in Philadelphia, PA and competes in the Eastern Conference of Major League Soccer (MLS), the top professional soccer league in the United States and Canada. The Union was established in February 2008 (16th club in the league) and is owned by Keystone Sports and Entertainment, LLC. The team plays their home matches at Subaru Park located on the banks of the Delaware River in Chester, PA.