Maryland Route 27

Maryland Route 27
Route information
Maintained by MDSHA
Length	39.17 mi[1] (63.04 km)
Existed	1934–present
Tourist routes	Historic National Road Old Main Streets Scenic Byway
Major junctions
South end	MD 355 near Germantown
Major intersections	MD 108 in Damascus MD 80 near Damascus I-70 / US 40 in Mount Airy MD 808 near Mount Airy MD 26 in Taylorsville MD 407 near Taylorsville MD 97 / MD 140 in Westminster MD 482 in Mexico
North end	MD 30 in Manchester
Location
Country	United States
State	Maryland
Counties	Montgomery, Howard, Frederick, Carroll
Highway system
Maryland highway system Interstate US State Scenic Byways
← MD 26 → MD 28

Maryland Route 27 (MD 27) is a state highway in the U.S. state of Maryland. Known for most of its length as Ridge Road, the highway runs 39.17 miles (63.04 km) from MD 355 in Germantown north to MD 30 in Manchester. MD 27 follows a ridge that separates several watersheds in northern Montgomery County and Carroll County. The highway connects Germantown and Manchester with Damascus in far northern Montgomery County; Westminster, the county seat of Carroll County; and Mount Airy, which lies at the junction of Carroll, Frederick, Howard, and Montgomery counties and where MD 27 intersects Interstate 70 (I-70)/U.S. Route 40 (US 40).

MD 27 follows what was originally MD 29 and part of MD 31. The highway received its present number south of Westminster in a swap with US 29 in 1934 and north of Westminster in 1967. Ridge Road south of Mount Airy and Manchester Road between Westminster and Manchester was constructed as one of the original state roads in the early to mid-1910s. The Mount Airy– Westminster portion of MD 27 was built in the 1920s. MD 27 was reconstructed in the early to mid-1950s from Germantown to Westminster. MD 31 was reconstructed north of Westminster in the late 1950s; old segments of the highway became part of MD 852. MD 27 bypassed Mount Airy in the 1970s, leaving behind MD 808. The highway was relocated at its southern end in the mid-1990s to improve access between Damascus and Germantown and I-270.