In late June 1863, the Confederate Army of Northern Virginia under General Robert E. Lee advanced over South Mountain to Cashtown along this route, also known as the Chambersburg Pike, with tens of thousands of men, horses, cannons, and wagons moving east toward Gettysburg, where they fought the Union Army of the Potomac under General George G. Meade in the Battle of Gettysburg on July 1st, 2nd, and 3rd. Residents along the road said the advance sounded like thunder. In the early morning of July 4th, 1863, after defeat by the Army of the Potomac, Lee ordered General John D. Imboden’s cavalry to protect a 17-mile-long Confederate ambulance train as it retreated west along the same road, now known as Old Route 30. Through torrential rain, the wagon train of wounded soldiers and its defending cavalry and artillery force withdrew through the Cashtown pass, and residents again heard thunder, now joined by the storm.
