Altoona is a city in Blair County, Pennsylvania, United States. It is the principal city of the Altoona, PA MSA. The population was 47,176 at the 2006 census estimate, making it the ninth most populous city in Pennsylvania, after Philadelphia, Pittsburgh, Allentown, Erie, Reading, Scranton, Bethlehem, Lancaster and Harrisburg. The Altoona MSA includes all of Blair County and had an estimated population of 125,527 in 2007, according to the U.S. Census. Having grown around the railroad industry, the city is currently working to recover from industrial decline and urban decentralization experienced in recent decades. The city is home to the Altoona Curve baseball team of the Double A Eastern League, which is the Double A affiliate of the Pittsburgh Pirates. It also houses the 75+ year-old Altoona Symphony Orchestra, under the direction of Teresa Cheung. Prominent landmarks include the Horseshoe Curve, the Railroaders Memorial Museum, the Mishler Theatre, the Cathedral of the Blessed Sacrament, and the Jaffa Mosque. Altoona is also the home of the Sheetz headquarters. Sheetz is one of the largest convenience store and gas station chains in the country, with stores in Pennsylvania, Maryland, Ohio, West Virginia, Virginia, and North Carolina. Because of this, many Sheetz stores are located in and around Altoona.