The New York, Providence and Boston Railroad, normally called the Stonington Line, was a major part of the New York, New Haven and Hartford Railroad between New London, Connecticut and Providence, Rhode Island. It is now part of Amtrak's high-speed Northeast Corridor.
On November 1, 1859 the NYP&B leased the New Haven, New London and Stonington Railroad, less than a year after its completion, giving it a line from Providence to New Haven, Connecticut, though with two ferries, one across the Thames River at New London and another across the Connecticut River. The terminal for steamboats connecting to the Long Island Rail Road was moved to Groton, on the east shore of the Thames River. In 1864, the NYP&B purchased the NHNL&S line east of Groton; the remainder was leased by the New York and New Haven Railroad in 1870.