In June 1972, tropical storm Agnes cause severe flooding in Pennsylvania and southern New York. The floods on many major strams were the highest known since the river valleys were settled. Maximum discharges were as much as twice the discharge of a 50-year flood. In central pennsylvania, large areas in Lock Have, Mill Hall, Wilkes-Barre, Kingston, Pittston, harrisburg, and in many smaller communities were inundated to depths of several feet.
The extent of the flooding shown on the map was delineated by the U.S. Geological Survey from field surveys made soon after the flood.
The investigation was conducted in cooperation with the Pennsylvania Department of Environmental Resources, the Susquehanna River Basin Commission, and the U.S. Army Corps of Engineers.