Maryland Route 31 (MD 31) is a state highway in the U.S. state of Maryland. Known for most of its length as New Windsor Road, the state highway runs from MD 26 in Libertytown east to MD 140 in Westminster. MD 31 connects the county seats of Frederick and Westminster via Libertytown in eastern Frederick County and New Windsor in western Carroll County. MD 31 originally extended from Frederick to Manchester, using the paths of what are now MD 26 and MD 27. MD 26 assumed MD 31 west of Libertytown in 1933 and MD 27 took over MD 31's route north of Westminster in 1967. The Westminster–Manchester portion of the state highway was constructed as one of the original state roads in the early 1910s. The remainder of the highway was built in the early to mid-1920s. MD 31 was relocated north of Westminster in the late 1950s and south of Westminster in the mid-1960s. The bypassed sections of the state highway became parts of MD 852. Route description MD 31 begins at an intersection with MD 26 (Liberty Road) on the eastern end of Libertytown. The state highway heads east as a two-lane undivided road through farmland that passes through a pair of curves in the hamlet of Oak Orchard before crossing Sams Creek into Carroll County at Englars Mill. After intersecting the western terminus of MD 407 (Marston Road) near the village of Marston, MD 31 veers north and crosses Little Pipe Creek into the town of New Windsor. The state highway crosses the east–west line of the Maryland Midland Railway and heads north through the New Windsor Historic District as High Street. A short distance north of Main Street, which heads east as unsigned MD 831J, MD 31 veers east to an intersection with Green Valley Road, which heads north as MD 75. MD 31 turns south onto Green Valley Road, then turns east onto Main Street one block east of its previous intersection with Main Street. Prior to leaving the town of New Windsor, MD 31 intersects Springdale Road, passes the historic Avalon, and meets the western end of its old alignment, which is named Old New Windsor Road and is unsigned MD 852. The old alignment parallels the present alignment to the north through the Wakefield Valley. MD 31 crosses Turkeyfoot Run and briefly parallels the railroad before meeting the other end of MD