Mertztown is a census-designated place in Longswamp Township in Berks County, Pennsylvania. It is located near the borough of Topton. As of the 2010 census, the population was 664 residents. Mertztown is located in Berks County at latitude 40.506 and longitude-75.665. Its elevation is 466 feet. It appears on the United States Geological Survey map for Topton and is in the Eastern Time Zone.