Maximum flood discharges for Hurricane Agnes, 1972, on 44 Pennsylvania watersheds were compared with historic flood records. Mathematical frequency curves were fitted to each series according to the Gumbel, log-Gumbel, and log-Pearson Type III methods. The 1972 floods were less than 4.8 times the average annual flood peak in all but 8 of the 44 cases. The threshold was established in previous studies as the ratio between a 1,000-year flood and an average annual flood, equivalent to about a 5% chance of being exceeded by a worse flood once or more in the next 50 years. Most locations have high probabilities of being struck by far worse floods than they experienced in 1972.