At its western end at the
Idaho state line, MT 200 follows the
Clark Fork River at the feet of the
Cabinet Mountains eastward for until it meets the
Flathead River at
MT 135. It then follows the Flathead River east for to
Sčilíp (formerly Dixon) where the Flathead River turns north. MT 200 continues east following the
Jocko River for and borders the
CSKT Bison Range until it intersects with
US 93 at
Ravalli. The two highways share a
concurrency and travel south
I-90, where they head east into
Missoula. MT 200 follows I-90 through Missoula for , with US 93 departing and US 12 joining the route along the way, leaving the interstate near
Milltown. The highway runs parallel to the
Blackfoot River and is subject to hazardous driving conditions in the winter, particularly due to
black ice. From I-90, the road travels east to
Lincoln, and another where it crosses
Rogers Pass on the
Continental Divide. It continues east for to
Bowman's Corner where it intersects
US 287, and then another to
Sun River where it merges with
US 89. The two highways travel for east to
I-15 near
Vaughn, where they join the interstate and travel south for to
Great Falls. In Great Falls, MT 200 and US 89 leave I-15, where they become concurrent with
MT 3, share a brief concurrency with
I-315 (I-15 Business), and merge with
US 87, following 10th Avenue South eastward through the city. The four routes of US 87, US 89, MT 3, and MT 200 share a concurrency from Great Falls to
Armington Junction (near
Belt), where US 89 heads south and the three remaining routes continue east for . At
Eddie's Corner (near
Moore), the routes meet
US 191 where MT 3 and US 191 share a common alignment to
Harlowton. US 87, US 191, and MT 200 share a concurrency to Lewistown, where US 191 heads north, and US 87/MT 200 continue another to
Grass Range. At Grass Range, MT 200 and US 87 end their concurrency and MT 200 continues east for to
MT 59 in
Jordan. MT 200 continues east to
Circle where it intersects
MT 13 and
MT 200S (an auxiliary route that connects MT 200 with
Glendive and
Interstate 94). It continues east until it intersects
MT 16 and
MT 23, where MT 16 and MT 200 head north into
Sidney and share a concurrency. MT 200 leaves Sydney and travels northeast for to
Fairview, where it turns east and crosses into
North Dakota. MT 200 follows the following
MDT corridors: ==History==