Maryland Route 135 (MD 135) is a state highway in the U.S. state of Maryland. Known for most of its length as Maryland Highway, the state highway runs 29.00 miles (46.67 km) from U.S. Route 219 (US 219) in Oakland in Garrett County east to US 220 in McCoole in Allegany County. MD 135 is the main link between the towns of Oakland, Mountain Lake Park, Loch Lynn Heights, and Deer Park on the Appalachian Plateau and the communities of Bloomington, Luke, Westernport, and McCoole in the upper valley of the North Branch Potomac River. These groups of towns are separated by Backbone Mountain.