...delphia (September, 1777) the Americans still held control of the Delaware River below that city. On Mud Island, near the confluence of the Schuylkill and Delaware, was built Fort Mifflin. On the New Jersey shore, opposite, at Red Bank, was Fort Mercer, a strong redoubt, well furnished with heavy artillery. At Billingsport, on the same shore, 3 miles lower down, were extensive but unfinished works des...