U.S. Route 87 in Montana

U.S. Highway 87 (US 87) is a north-south United States Numbered Highway in the state of Montana. It extends approximately 444.4 mi from the Wyoming state line north to its terminus at US 2 near Havre.

Route description
US 87 enters Montana running concurrently with Interstate 90 (I-90) and travels westward for 45.3 mi to Crow Agency, where US 212 merges with the route. The three routes continue westward for another 54.6 mi to Billings, where it intersects with the western terminus of I-94 in suburban Lockwood. US 87 follows the I-90/US 212 concurrency for another 3.3 mi before it heads north, following Main Street through Billings Heights. US 87 continues north for 51 mi and intersects US 12, sharing a 2.1 mi concurrency through Roundup. US 87 continues north with a slight bend to the northwest for 44.7 mi until it intersects Montana State Highway 200 (MT 200) near Grass Range and takes a sharp turn west; US 87 remains concurrent with MT 200 until Great Falls. US 87 and MT 200 travel west for 30.6 mi to Lewistown, where they merge with US 191 and continue heading generally westward. About 14.3 mi west of Lewistown near Moore, it breaks with US 191 and merges with MT 3, where they head northwest for 64.7 mi and merge with US 89 near Armington. The four-route concurrency of US 87/US 89/MT 3/MT 200 continues northwest for 22.7 mi to Great Falls, where US 87 leaves all three and travels north through the city. North of Great Falls, US 87 travels northeast for 37.4 mi to Fort Benton and a final 70 mi to its terminus with US 2, about 2 mi west of Havre.

History
US 87 originally ran northwest out of Great Falls towards the eastern border of Glacier National Park to the Canadian Border at the Piegan Border Crossing. This was changed in 1934, when US 89 was diverted to US 87's routing north of Great Falls. US 87 ended in Great Falls until c. 1945 when it was extended to its current northern terminus near Havre.

Special routes
The following are special routes of U.S. Route 87 in Montana.

Great Falls
U.S. Highway 87 Bypass (US 87 Byp.) exists on the eastern and northern edge of Great Falls. The route begins at 10th Avenue South (US 87/US 89/MT 3/MT 200) west of Malmstrom Air Force Base along 57th Street South and runs south to north. Just south of the intersection with 2nd Avenue North the name of the road changes to 57th Street North. At 10th Avenue North, the street name changes to River Drive North, then curves towards the west as it crosses a bridge over a former Milwaukee Road railroad line. The route heads straight west until after the intersection of North Park Trail where it curves to the northwest. After a railroad crossing and the entrance to Giant Springs State Park and the Lewis and Clark Interpretive Center, the road curves to the southwest, generally following the south bank of the Missouri River. US 87 Byp. ends at US 87 south of the 15th Street Bridge, but River Drive North continues along the Missouri River through Riverside Park. It is known internally by Montana Department of Transportation as Corridor N-102 (C005205).

Lewistown
U.S. Highway 87 Bypass (US 87 Byp.) in Lewistown, also known as the Truck Bypass, is an unsigned highway follows the northern and western edge of the city. The route begins at Main Street (US 87/MT 200), just east of downtown, and follows 1st Avenue North to Kendall Road (US 191 north), where the roadway turns westward becoming 6th Avenue North and also becomes part of US 191. Just west of Lewistown, the roadway turns southwest and re-joins US 87/MT 200. US 87 Byp. is unsigned as the majority of the route is signed as part of US 191. It is known internally by Montana Department of Transportation as part of Corridor N-43 (C000043) and N-75 (C000075).