The Framingham Subdivision is a railroad line owned by CSX Transportation in the U.S. state of Massachusetts. The line runs from Mansfield northwest to Framingham along a former New York, New Haven and Hartford Railroad line. Its south end is at Amtrak's Northeast Corridor, over which CSX has trackage rights to reach the Middleboro Subdivision at Attleboro and the Boston Subdivision in Boston (via the Dorchester Branch). Its north end is at the Boston Subdivision; the Fitchburg Subdivision continues northwest from Framingham.
The entire line opened in 1869 as the Mansfield and Framingham Railroad. It became part of the NYNH&H and Conrail through leases, mergers, and takeovers, and was assigned to CSX in the 1999 breakup of Conrail.