The Chicxulub impact 65 Ma triggered massive submarine failure of continental margins around the North Atlantic. Slumped sediments associated with impact ejecta and geochemical tracers of the bolide are present on the Blake Plateau, the mid-Atlantic continental slope and rise, Bermuda Rise, and the Iberian Abyssal Plain more than 6000 km from the impact crater. Evidence from deep-sea drilling and seismic stratigraphy suggests that much of the eastern seaboard of North America and at least parts of the eastern margin of the North Atlantic must have failed catastrophically because of the approximately 10-13 magnitude earthquake associated with the impact event, and created one of the largest, composite mass-wasting deposits on Earth. We infer that mass failure of the eastern margin of North America can account for elevated extinction rates and delayed recovery of North American invertebrates compared to other places during the Cretaceous-Paleogene mass extinction. Slumping on the margins also redeposited large volumes of carbonates into the deep sea below the Cretaceous carbonate compensation depth (CCD), giving the false impression of a drop in the CCD during the Maastrichtian.