Maryland Route 845 (MD 845) is an unsignedstate highway in the U.S. state of Maryland. Known for most of its length as Main Street, the state highway runs 1.23 miles (1.98 km) between intersections with MD 34 on either side of Keedysville in southern Washington County. MD 845, which is officially MD 845A, is the old alignment of MD 34 through Keedysville. The state highway was designated around 1960 when MD 34 bypassed the town.
MD 845 begins at an intersection with MD 34 (Shepherdstown Pike) just south of the town of Keedysville. Keedysville Road heads northwest on the opposite side of the intersection as a county highway that passes by Hills, Dales and The Vinyard, Hitt's Mill and Houses, and the Hoffman Farm. MD 845 heads southeast then immediately curves to the northeast as two-lane Main Street, entering the town limits and the Keedysville Historic District. The state highway intersects Dogstreet Road, which leads to the historic Geeting and Snively farms, before crossing over Little Antietam Creek. MD 845 intersects an abandoned Baltimore and Ohio Railroad grade before reaching an intersection with Keedy Drive on the north side of town. Main Street continues as a municipal street to a dead end while the state highway turns onto Keedy Drive to reach its northern terminus at MD 34.