The Eastman tunnel, also called the Hennepin Island tunnel, was a 2,000-foot-long (610 m) underground passage in Saint Anthony, Minnesota, (now Minneapolis) dug beneath the Mississippi River riverbed between 1868 and 1869 to create a tailrace so water powered business could be located upstream of Saint Anthony Falls on Nicollet Island. The tunnel ran downstream from Nicollet Island, beneath , and exited below Saint Anthony Falls. The Eastman tunnel is a contributing resource to the St. Anthony Falls Historic District. The District is on the National Register of Historic Places