Known as Main Street, the state highway runs 2.62 miles (4.22 km) between two intersections with U.S. Route 113 (US 113) on the north and south sides of Berlin in Worcester County.

The state highway was designated shortly after US 113's bypass of Berlin was completed in the late 1950s.

After passing the Calvin B. Taylor House Museum, MD 818 leaves the downtown area.

The state highway crosses the Snow Hill Line of the Maryland and Delaware Railroad at a rakish angle before intersecting MD 346 (Old Ocean City Boulevard) and leaving the town of Berlin.

The state highway continues north, crossing the railroad track again before reaching its northern terminus at US 113.