Summerdale is located at 40°17'25" North, 76°56'4" West (40.293538, -76.926346).
According to the United States Census Bureau, Summerdale has a total area of 0.1 square miles (0.3 km²). 0.1 square miles (0.3 km²) of it is land and none of the area is covered with water. It is located on the west side of U.S. Route 11/15 and south side of Interstate 81. These two highways interchange just north of Summerdale.
Summerdale is a normal town, but the people of Summerdale find ways to have fun. The main attractions in Summerdale include: Central Pennsylvania College, Capitol Area Intermediate Unit, and Summerdale United Methodist Church. Summerdale was founded in 1909. As people from Harrisburg came over the river during the summers, a dance hall was erected to support their need to party, thus, starting the town of Summerdale. In 2009, Summerdale held a Centennial Celebration. There was a parade, games, and a year-long celebration dedicated to the small town of Summerdale.