Portsmouth was a propeller-driven steamship, launched at Buffalo, New York in 1853. Portsmouth measured 176 feet long, with a beam of 29 feet and a depth-of-hold of ten feet. She was originally registered at Buffalo, New York, and operated on Lake Eire.

On November 10, 1867, Portsmouth was carrying a bulk cargo of pig iron when she was driven ashore by a storm near the northern end of Middle Island, on the upper reaches of Lake Huron. All aboard escaped, but the ship later caught fire and burned to the waterline.

Although no lives were lost in the wreck of Portsmouth, the loss of one of the Great Lakes' larger steamers pointed up the hazards of the coast, and helped to justify the establishment of a U.S. Life Saving Station at Middle Island.

Although Portsmouth was not a focus of the field school's archaeological investigations, during the project several team members took the opportunity to snorkel on the wreck, and took the opportunity to photograph the wreck to record its general appearance and condition.