Montana Highway 3 (MT 3) is a highway in central Montana extending north from Billings to Great Falls.^[2][3]

Quick Facts Route information, Length ...

Montana Highway 3
MT 3 highlighted in red
Route information
Maintained by MDT
Length	221.770 mi[1] (356.904 km)
Major junctions
South end	I-90 / US 212 in Billings
Major intersections	US 12 from Lavina to Harlowton US 191 from Harlowton to Moore US 87 in Moore US 89 in Armington US 87 in Great Falls
North end	I-15 / US 89 in Great Falls
Location
Country	United States
State	Montana
Highway system
Montana Highway System Interstate US State Secondary
← MT 2 → MT 5

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At its southern end, MT 3 begins at I-90 in Billings and travels northwest 47 miles (76 km) to US 12 near Lavina – this is the only section of MT 3 that is not concurrent with a US highway. MT 3 joins US 12 and travels 45 miles (72 km) west to Harlowton, where it leaves US 12 and joins US 191, and travels north for 39 miles (63 km) to Eddie's Corner (near Moore). At Eddie's Corner, MT 3 turns west, leaving US 191 and joining the US 87 / MT 200 concurrency, and travels west 65 miles (105 km) to Armington where US 89 joins the highway. The four highways continue 23 miles (37 km) to Great Falls, where it follows a 0.8-mile (1.3 km) concurrency with I-315 and ends at I-15.^[1][3]

MT 3 is part of the Camino Real Corridor (Corridor 27), a High Priority Corridor that connects El Paso, Texas to the Canada–United States border at Sweet Grass, Montana. The corridor is anchored by Interstate 25 and is part of the larger Ports-to-Plains Alliance. MT 3 is connected to the Canadian border via I-15, and is connected to I-25 in Buffalo, Wyoming via I-90.^[4]