where did the johnstown flood happen?
A+E Networks. The South Fork Dam collapses on this day in 1889, causing a flood in Johnstown, Pennsylvania, that kills more than 2,200 people. Johnstown is 60 miles east of Pittsburgh in a valley near the Allegheny, Little Conemaugh, and Stony Creek Rivers. It is located on a floodplain that has been subject to frequent disasters.