TY - JOUR T1 - The Mighty Susquehanna—Extreme Floods in Eastern North America During the Past Two Millennia JF - Geophysical Research Letters Y1 - 2019 A1 - Toomey, Michael A1 - Cantwell, Meagan A1 - Colman, Steven A1 - Cronin, Thomas A1 - Donnelly, Jeffrey A1 - Giosan, Liviu A1 - Heil, Clifford A1 - Korty, Robert A1 - Marot, Marci A1 - Willard, Debra AB - The hazards posed by infrequent major floods to communities along the Susquehanna River and the ecological health of Chesapeake Bay remain largely unconstrained due to the short length of streamgage records. Here we develop a history of high‐flow events on the Susquehanna River during the late Holocene from flood deposits contained in MD99‐2209, a sediment core recovered in 26 m of water from Chesapeake Bay near Annapolis, Maryland, United States. We identify coarse‐grained deposits left by Hurricane Agnes (1972) and the Great Flood of 1936, as well as during three intervals that predate instrumental flood records (~1800–1500, 1300–1100, and 400–0 CE). Comparison to sedimentary proxy data (pollen and ostracode Mg/Ca ratios) from the same core site indicates that prehistoric flooding on the Susquehanna often accompanied cooler‐than‐usual winter/spring temperatures near Chesapeake Bay—typical of negative phases of the North Atlantic Oscillation and conditions thought to foster hurricane landfalls along the East Coast. VL - 46 UR - https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018GL080890 IS - 6 ER -