Known as Bayard Road, the highway runs 3.04 miles (4.89 km) from Polling House Road near Lothian east to MD 2 and MD 408 at Lothian in southern Anne Arundel County.

MD 422 begins at Polling House Road west of Lothian.

MD 422 heads east as a two-lane undivided road through farmland.

After passing South Polling House Road, which meets Polling House Road in Harwood, the highway turns southeast toward its terminus at a four-legged roundabout in the village of Lothian.

MD 2 (Solomons Island Road) heads southeast toward Prince Frederick and northeast in the direction of Annapolis; MD 408 (Mount Zion-Marlboro Road) heads southwest toward Upper Marlboro.