The Susquehanna Trail was an auto trail in the United States linking Washington, D.C., with Niagara Falls, New York. It passed through Baltimore, Maryland; Harrisburg, Pennsylvania; Williamsport, Pennsylvania; and Buffalo, New York.
In relatively modern terms, the Susquehanna Trail roughly followed the following highways:
- U.S. Route 1, Washington, D.C., to Baltimore, Maryland
- U.S. Route 111 (now MD Route 45, Interstate 83 Business and other minor routes), Baltimore to Harrisburg, Pennsylvania
- U.S. Route 22, Harrisburg to Duncannon, Pennsylvania
- U.S. Route 11, Duncannon to Northumberland, Pennsylvania
- PA Route 147, Northumberland to Muncy, Pennsylvania
- U.S. Route 220, Muncy to Williamsport, Pennsylvania
- U.S. Route 15, Williamsport to Wayland, New York
- NY Route 63, Wayland to Dansville, New York
- NY Route 36, Dansville to Leicester, New York
- U.S. Route 20A, Leicester to East Aurora, New York
- NY Route 16, East Aurora to Buffalo, New York
- NY Route 5 and U.S. Route 62, Buffalo to Niagara Falls, New York
An alternate ran from Washington to Harrisburg via U.S. Route 240 and U.S. Route 15 through Frederick, Maryland.
