Swatara Creek forms the northwest border of the township, except where the border is with the borough of Hummelstown. Geography ĭerry Township is located in southeastern Dauphin County, bordered to the east by Lebanon County. The Derry Session House and Enclosure and Quarries of the Hummelstown Brownstone Company are listed on the National Register of Historic Places. Conewago Township was created in 1850 from southern parts of Derry Township and eastern parts of Londonderry Township. In 1787, the township's population was 198. ĭerry and Londonderry became a part of Dauphin County when it was established in 1785. In 1767 the court ordered the division of Derry Township, the eastern section to remain Derry and the western to be Londonderry Township. The number of elected officials in Derry remains five, although the terms are now six years. Five officials were elected for one-year terms. The first official government in Derry Township was established in 1759. At that time, the boundaries of Derry Township were much larger and included what are currently three other townships within Lancaster and Dauphin counties. The Township of Derry was incorporated on August 1, 1729, when Lancaster County partitioned its territory for tax purposes.

Hershey Medical Center and the Penn State Hershey Children's Hospital are also located on a large tract of land in the township. Pennsylvania State University's Milton S. Hershey, the site of the well-known Hershey's chocolate factory and its affiliated amusement park, is located within the township.

The population was 24,796 at the 2020 census, an increase over the figure of 24,679 tabulated in 2010. Derry Township is a township in Dauphin County, Pennsylvania, United States.

Derry township pool