Maryland Route 119, also known as Great Seneca Highway, is a north–south Maryland state highway that runs from Maryland Route 28 in Rockville to Middlebrook Road in Germantown.

Maryland Route 119 begins at a wide intersection at MD 28 (Key West Avenue), beginning in Rockville on the four-lane divided Great Seneca Highway. It winds to the northwest, passing through a wooded suburban residential area and eventually passing by a large shopping center as it intersects MD 124. Beyond this intersection, MD 119 enters a stretch of forest and curves to the north, emerging from said forest after crossing a transmission line. Nearing Germantown, the residential areas pick up once again, and the route curves a bit more before it crosses a creek and finds its northern terminus at Middlebrook Road near Seneca Valley High School.

The entire route is in Montgomery County.