Rehrersburg is a census-designated place in Tulpehocken Township in northwestern Berks County, Pennsylvania, United States, near Pennsylvania Route 419. The community was founded on April 4, 1803, by John Jacob Rehrer. Residents celebrated the town's bicentennial on Saturday, September 20, 2003. As of the 2010 census, the population was 319 residents. In 1818, the sixth post office in the county opened in Rehrersburg. Rehrersburg's ZIP code is 19550.