Maryland Route 189, better known as Falls Road, is a road in Montgomery County, Maryland. The road runs from River Road in Potomac northeast to Maryland Avenue in Rockville. Formerly, Route 189 ran from MacArthur Boulevard in Potomac to Maryland Route 28 in the center of Rockville.

Maryland Route 189 begins at an intersection with MD 190 (River Road) in Potomac. Following Falls Road north on a two-lane undivided alignment, the route exits a commercial area and travels to the north, curving through a residential area with several side streets to more homes. The route, largely wooded, also provides access to many of Potomac's services, such as a community center and a fire department. The route curves to the east at a very wide intersection near Potomic Tennis Lane and passes south and east of a large golf course. Re-entering the wooded area, MD 189 passes by several school buildings amid the homes, before a large transmission line clearing crosses the road. The route returns to residential development, dualizing shortly before it meets Interstate 270 at a single-point urban interchange. The Maryland route designation is dropped at the very next intersection, and the two carriageways combine and continue north as Great Falls Road.

As part of a route swap with Montgomery County, the state of Maryland truncated the route in the late 1990s (year uncertain); the southern terminus is now at Maryland 190, and the northern terminus is now at the intersection of Great Falls Road and Maryland Avenue just north of I-270 exit 5.

The entire route is in Montgomery County.