Chickies Rock is a unique geological feature along the Susquehanna River known as an anticline, an arch of exposed rock arranged in layers that bend in opposite directions from its peak. Chickies is classified as the largest example of its kind on the East Coast. This particular location also played a significant role during the Civil War. As a highpoint along the Susquehanna River, the bluff was a strategic location for the Union Army during the Confederate’s occupation of Wrightsville across from Columbia during the Gettysburg Campaign. Later the Columbia and Donnegal Electric Railway would build a trolley line north from Columbia to the peak of the Rocks where it also constructed an amusement park. The line scaled 1900 feet up the west side of Chickies Hill Road on a 6% grade abruptly turning toward the peak to access the park. Opening in 1893 the line later extended down to Marietta providing both towns access to the popular recreation area. The trolley line and park continued to operate until its abandonment in April of 1932.
Looking to the north from Chickies Rock one can see the PRR York Haven line, the former alignment of the Columbia branch and the town of Marietta. The rail lines converge at the base of the rocks to squeeze south (railroad east) on a narrow flat along side the Susquehanna River. It was at this location during the construction of the low-grade that the PRR decided it would build the York Haven line out on a fill to avoid the curving profile of the older alignment between here and Columbia. As a result Kerbaugh Lake, named after one of the biggest contractors on the low-grade project was created. Though referred to as a lake the area was really a low laying swamp with poor drainage that separated the two alignments. In 1936 the flood prone Susquehanna rose to levels that consumed the new fill destroying the vital low-grade, flooding Kerbaugh Lake and the Columbia branch along the shore. The devastation required months to rebuild the York Haven line and forced the decision to abandon the older Columbia branch alignment. During this period the PRR also filled in Kerbaugh Lake and improved drainage in the area by installing several culverts between the lake and Susquehanna under the right of way. Today most of this area is part of the Chickies Rock Park operated by the Lancaster County Parks Department and provides some beautiful views along various trails following the former Columbia branch between Marietta and old Kerbaugh Lake in addition to park high above on Chickies Rock itself.