MD 119 begins at an intersection with MD 28 (Key West Avenue) in an unincorporated area west of the city of Rockville.
Great Seneca Highway continues south as a county highway to Darnestown Road and provides access to Shady Grove Adventist Hospital, the Universities at Shady Grove, and the Montgomery County campus of Johns Hopkins University.
MD 119 heads northwest as a four-lane divided highway.
The highway crosses over Shady Branch twice around its intersection with Sam Eig Highway, a county highway that connects MD 119 with I-370, I-270, MD 200, and the Shady Grove station along Washington Metro's Red Line.
At the county highway, MD 119 enters the city of Gaithersburg and temporarily expands to six lanes until its intersection with Muddy Branch Road.
The highway crosses Muddy Branch and passes along the edge of the New Urbanist community of Kentlands before intersecting MD 124 (Quince Orchard Road).

MD 119 leaves the city of Gaithersburg and passes through Seneca Creek State Park.
The highway does not provide access to the state park; the only park road the highway meets, Deer Ridge Road, passes over the state highway.
Within the park, MD 119 crosses Long Draught Branch and Great Seneca Creek.
On the western edge of the park, the state highway passes a Washington Suburban Sanitary Commission water treatment facility and enters the unincorporated suburb of Germantown.
MD 119 curves north as it intersects Richter Farm Road and passes Northwest High School.
The highway crosses Gunners Branch and intersects MD 117 (Clopper Road).
MD 119 curves northeast to cross CSX's Metropolitan Subdivision, which carries MARC's Brunswick Line.
The highway curves back north and intersects Wisteria Drive before reaching its northern terminus at Middlebrook Road next to Seneca Valley High School.
Middlebrook Road is a county highway that provides access to MD 118 and the Germantown MARC station to the west and I-270 and MD 355 to the east.

MD 119 is a part of the National Highway System as a principal arterial for its entire length.
MD 119 begins at an intersection with MD 28 (Key West Avenue) in an unincorporated area west of the city of Rockville. Great Seneca Highway continues south as a county highway to Darnestown Road and provides access to Shady Grove Adventist Hospital, the Universities at Shady Grove, and the Montgomery County campus of Johns Hopkins University. MD 119 heads northwest as a four-lane divided highway. The highway crosses over Shady Branch twice around its intersection with Sam Eig Highway, a county highway that connects MD 119 with I-370, I-270, MD 200, and the Shady Grove station along Washington Metro's Red Line. At the county highway, MD 119 enters the city of Gaithersburg and temporarily expands to six lanes until its intersection with Muddy Branch Road. The highway crosses Muddy Branch and passes along the edge of the New Urbanist community of Kentlands before intersecting MD 124 (Quince Orchard Road).
MD 119 leaves the city of Gaithersburg and passes through Seneca Creek State Park. The highway does not provide access to the state park; the only park road the highway meets, Deer Ridge Road, passes over the state highway. Within the park, MD 119 crosses Long Draught Branch and Great Seneca Creek. On the western edge of the park, the state highway passes a Washington Suburban Sanitary Commission water treatment facility and enters the unincorporated suburb of Germantown. MD 119 curves north as it intersects Richter Farm Road and passes Northwest High School. The highway crosses Gunners Branch and intersects MD 117 (Clopper Road). MD 119 curves northeast to cross CSX's Metropolitan Subdivision, which carries MARC's Brunswick Line. The highway curves back north and intersects Wisteria Drive before reaching its northern terminus at Middlebrook Road next to Seneca Valley High School. Middlebrook Road is a county highway that provides access to MD 118 and the Germantown MARC station to the west and I-270 and MD 355 to the east.
MD 119 is a part of the National Highway System as a principal arterial for its entire length.
Maryland Route 119