Maryland Route 166

Maryland Route 166
Maryland Route 166 highlighted in red
Route information
Maintained by MDSHA
Length	2.71 mi[1] (4.36 km)
Existed	1927–present
Major junctions
South end	I-195 in Arbutus
Major intersections	MD 372 in Catonsville
North end	MD 144 in Catonsville
Location
Country	United States
State	Maryland
Counties	Baltimore
Highway system
Maryland highway system Interstate US State Scenic Byways
← MD 165 → MD 168

Maryland Route 166 (MD 166) is a state highway in the U.S. state of Maryland. The state highway runs 2.71 miles (4.36 km) from Interstate 195 (I-195) in Arbutus north to MD 144 in Catonsville. MD 166 consists of two sections: a short freeway section that serves as a northern continuation of I-195 and provides access to the University of Maryland, Baltimore County (UMBC), and a segment of Rolling Road, a major north–south highway in western Baltimore County. Rolling Road dates to the colonial era as a highway used to transport tobacco from plantations to river ports. North Rolling Road, which connects Catonsville with Woodlawn and Milford Mill, has always been a county highway. South Rolling Road was constructed as a state highway by the early 1920s between what were to become U.S. Route 1 (US 1) and US 40. Parts of South Rolling Road were transferred to county maintenance after they were severed by the construction of I-95 and a freeway relocation of the southern end of MD 166 in the early 1970s.