Philadelphia is located at the south side of the broad Cogamus River Valley, which flowed into the Hermus River near Sardis. The ancient Acropolis was built on an elevated spur of the Tmolus Mountain. A hollow can be seen in the Acropolis where the ancient stadium was located.
Because of its geographical location Philadelphia served as a gateway into the ancient kingdoms of Lydia and Phrygia.
The modern city of Alasehir is built over the remains of the ancient city of Philadelphia, so that few archaeological remains are visible today.