The Conowingo Dam on the Susquehanna River in Cecil County, Maryland.

The Conowingo Dam (also Conowingo Hydroelectric Plant, Conowingo Hydroelectric Station) is a large hydroelectric dam in the lower Susquehanna River near the town of Conowingo, Maryland. The medium-height, masonry gravity dam is one of the largest non-federal hydroelectric dams in the U.S. The dam sits about 9.9 miles from the river mouth at the Chesapeake Bay, 5 miles south of the Pennsylvania border and 45 miles northeast of Baltimore, on the border between Cecil and Harford counties. The dam supports a 9,000-acre reservoir, which today covers the original town of Conowingo. During dam construction, the town was moved to its present location about 1-mile northeast of the dam's eastern end.