In 1790, Captain Jacob Gearhart, a hero of the Revolutionary War, moved with his family by wagon train from new Jersey to the present day Riverside area. During the war Captain Gearhart was in charge of the boats at Washington's Crossing of the Delaware river. He also fought at the Battle of Brandywine and stayed the winter of 1777-78 at Valley Forge. Jacob built a log house overlooking the Susquehanna River and established a ferry service across it to Danville. A public road was then laid out from Sunbury to what was then known as Gearhart's Ferry. In 1804, a turnpike was built to Pottsville and the construction of these two roads had brought business to the ferry and prosperity to the Gearhart family. Up until the end of the Civil War the Riverside area was sparsely populated with only a few families including the Cars, the Boys, the Depews and the Gearharts. Post war prosperity brought many would-be settlers into the area and with the prospect of a new major railroad on the south bank of the river made the land even more desirable.The land was laid out in lots of 50 by 184 feet with wide avenues and streets between. O.H. Ostrander was appointed surveyor and real estate agent by the land association. In less than two years, forty buildings had been constructed in the newly charged Borough of Riverside. The great demand for real estate prompted the purchase of 30 adjoining acres from William Faux and 12 acres from Samuel Gulick in 1869.

A depression hit in 1873 resulting in the shutdown of the Danville iron mills and the unemployment of thousands. Many of the new homes in Riverside were foreclosed and sold in Sheriff's sales at one-third their value. After several years, the businesses of Danville, Riverside and South Danville revived and many of the people were able to buy back their homes. Construction began a new and by 1906 there were more than 1000 people and 160 buildings in Riverside and South Danville. The two communities remained separate until 1950 when the newly arrived Merck and Company agreed to treat the community sewage if they would install the mains. In order to take advantage of this offer it became necessary for the two communities to merge. Petitions were approved by the court to combine Gearhart Township with Riverside.