Crater Location (IMAGE) Arizona State University Caption The location of the crater in Chesapeake Bay. It is now completely covered by younger sediments, but was discovered in the early 1990s by marine geophysical surveys and subsequent drilling. It is the largest known impact crater in the U.S. and the 15th-largest on Earth. Credit Powars et al. 2015, Christoph Kersten / GEOMAR Usage Restrictions With permission from GEOMAR License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.