Rock Creek Assessment
The first known reference to the creek dates back to 1766 when it is shown on a survey map for the William Penn family and was referred to by the name Rock Run. The name is derived from the large diabase boulders, known locally as “Gettysburg Granite.” The boulders were formed in the Triassic age when molten rock was forced into the cracks of the existing shale and sandstone. The boulders are evident today in areas like Devil’s Den, Culp’s Hill, and Big and Little Round Tops.
Although there are no known early Native American settlements, Rock Creek was used as a fishing and hunting ground by several North American tribes. Spears and arrowheads can still be found along the banks of the creek.
By 1740, one of the first mills in the area was built along Rock Creek. The McAllister family purchased the mill in 1822 and it became one of the first stops on the Underground Railroad for slaves escaping northward. Ironically, the mill served as a Confederate Hospital during the Civil War. The largest field hospital for the Battle of Gettysburg was located between White Run and Rock Creek. The wounded were laid along the streambanks and were swept to their deaths by high waters when a severe storm struck the area on July 5, 1863.
In the 1930’s the Creek was used for recreation such as swimming and fishing as reported at a public meeting from a long time resident of the watershed. Today, Rock Creek is considered locally as the most impacted creek in the County.