Mertztown is a census-designated place in Longswamp Township, Berks County, Pennsylvania. It is located near the borough of Topton. As of the 2010 census, the population was 664 residents.The former Reading Railroad that runs through the center of Mertztown, is used by Norfolk Southern as the Reading Line, and it is a heavily used railroad branch. A branch of the Catasauqua and Fogelsville Railroad used to go through the Farmington and Klines Corner section of Mertztown but the tracks were torn up years ago.Mertztown was founded in 1823 by Robert Mertz. Atlas Minerals, a big mineral company, is located in Mertztown, moved to the town in 1917, and has been there ever since. The town is down to one Grocery Store, Radcliffe's Great Value, and two Hardware stores, True Value and the Menonite Hardware store.