About: Maryland Route 491

Maryland Route 491 (MD 491) is a state highway in the U.S. state of Maryland. Known for most of its length as Raven Rock Road, the state highway runs 6.78 miles (10.91 km) from MD 64 in Smithsburg north to MD 550 in Fort Ritchie. The middle portion of MD 491 was constructed in the mid-1950s. The highway was extended south to Smithsburg along a partially new alignment in the early 1960s, replacing a road that had been designed MD 92 from the mid-1930s to the mid-1950s. MD 491 was extended north toward Fort Ritchie in the late 1960s.