The Middletown Subdivision is a railroad line owned by CSX Transportation in the U.S. State of Ohio. The line runs from New Miami, Ohio. to Middletown, Ohio, for a total of 11.2 miles. At its south end it branches off of the Toledo Subdivision at Middletown Junction and at its north end the line branches off thru than enters , after crossing the Norfolk Southern Dayton District on the High Line or on a diamond the line continues north with the track ending at .