American Eagle Outfitters ( AEOS) set plans to move its headquarters to Pittsburgh from the nearby suburb of Warrendale.The retailer said it agreed to pay $21 million for a 186,000-square-foot building and adjacent land in the city's SouthSide Works, a so-called lifestyle retail-and-housing complex built on a 34-acre former LTV steel mill site on the city's South Side. American Eagle said it will reside at 77 Hot Metal St., featuring a riverfront location, city views and a walking trail in an urban location with restaurants and shops nearby. "After several years of successful growth and expansion, we have simply outgrown our current facility," said CEO Jim O'Donnell. "We are fortunate to have a retail powerhouse like American Eagle call Allegheny County its home," said Allegheny County Chief Executive Dan Onorato. "The company's decision to move its headquarters to the South Side and expand its operations in Marshall Township sends a strong message that Allegheny County is a great place to do business." On Friday, American Eagle slipped 36 cents to $23.24.