Maryland Route 77 is a state highway in the U.S. state of Maryland. The state highway runs 20.74 miles (33.38 km) from MD 64 in Smithsburg east to MD 194 in Keymar. MD 77 is the main east–west highway of northern Frederick County. The state highway connects Thurmont with eastern Washington County via Foxville, which lies between South Mountain and Catoctin Mountain near Catoctin Mountain Park and Cunningham Falls State Park. MD 77 links Thurmont with western Carroll County through the communities of Graceham, Rocky Ridge, and Detour in the Monocacy River valley. MD 77 was constructed from Thurmont east to Detour in the 1920s and early 1930s. A disjoint section of MD 77 was built between Cavetown and Foxville in the late 1930s. The portions of the modern highway between Foxville and Thurmont and from Detour to Keymar were county highways until they were designated part of MD 77 in 1956. MD 77's western terminus was moved east to MD 64 in Smithsburg in 1960.

Maryland Route 194 (MD 194) is a state highway in the U.S. state of Maryland. The state highway runs 23.87 miles (38.42 km) from MD 26 in Ceresville north to the Pennsylvania state line near Taneytown, where the highway continues as Pennsylvania Route 194 (PA 194) toward Hanover. MD 194 is the main highway between Frederick and Hanover; the state highway connects the towns of Walkersville and Woodsboro in northeastern Frederick County with Keymar and Taneytown in northwestern Carroll County. MD 194 was blazed as a migration route in the 18th century and a pair of turnpikes in Frederick County in the 19th century, one of which was the last private toll road in Maryland. The state highway, which was originally designated MD 71, was built as a modern highway in Frederick County in the mid-1920s and constructed as Francis Scott Key Highway in Carroll County in the late 1920s and early 1930s. MD 194 received its modern route number in 1956 as part of a three-route number swap. The state highway's bypasses of Walkersville and Woodsboro opened in the early 1980s and mid-1990s, respectively.