I remember Agnes. The creek I used to jump across on walks was almost 1/4 mile wide during the worst of the flooding. Our town was cut off by water. One of my most enduring memories is watching a nearby field where a herd of desperate Holsteins clung together on a little hillock in the flood, screaming. The water rose and rose about them. When I looked an hour later, the hillock was well underwater and the cattle were gone.
It caused bad flooding in Virginia, especially in Richmond, and Maryland but I think Pennsylvania got the worst of it.
The Pennsylvania Center for the Book - Hurricane Agnes