what is the county of allentown,pa
Allentown, PA. Online Offers. Allentown is a city located in Lehigh County, Pennsylvania, in the United States. It is Pennsylvania's third most populous city, after Philadelphia and Pittsburgh, and the 215th largest city in the United States. As of the 2010 census, the city had a total population of 118,032 and is currently the fastest growing city in Pennsylvania. It is also the county seat of Lehigh County.