STS073-741-064 Upper Chesapeake Bay, Maryland, U.S.A. October 1995 Clouds cover the mouth of the Susquehanna River in Chesapeake Bay in this north-northwest-looking, low-oblique, color-infrared view. Chesapeake Bay, the largest estuary in the United States, is the drowned river valley of the Susquehanna River, which originally flowed into the Atlantic Ocean east of present-day Norfolk, Virginia. Ice Age (Pleistocene) glaciers retreated nearly 10000 years ago; as the ice melted sea level rose and the original channel was drowned. The city of Baltimore and the bridge over the Petapsco River are discernible in the upper left portion of the image. On Delmarva Peninsula (lower half of image) the Chester River flows westward and empties into Chesapeake Bay just north of Kent Island (bottom left). Agricultural fields on Delmarva Peninsula are visible as paler red patches, contrasting with dark red forested areas.