the galleria at pittsburgh mills, or simply pittsburgh mills, is a super-regional shopping center northeast of pittsburgh, pennsylvania in frazer township, along pa route 28 near its intersection with the pennsylvania turnpike. the mall is the second largest shopping complex in western pennsylvania , the main retail center for the allegheny valley, as well as one of the largest in the state, with approximately 2 million square feet (186,000 m²) of retail space on . king of prussia near philadelphia remains the largest mall. the grand opening of the mall portion of pittsburgh mills was on july 14, 2005.