Interstate 115

Interstate 115
Interstate 115 highlighted in red
Route information
Maintained by MDOT
Length:	1.194 mi (1.922 km)
Existed:	1971 – present
Major junctions
West end:	I‑15 / I‑90 in Butte
East end:	I‑15 Bus. / I‑90 Bus. in Butte
Highway system
Interstate Highway System Main Auxiliary Suffixed Business Montana Highway System Interstate U.S. State Secondary ← I‑94 MT 117 →

Interstate 115 (I-115) is a short auxiliary Interstate Highway which connects Interstate 15/90 to Butte in the U.S. state of Montana. The highway is 1.19 miles (1.92 km) long and is overlapped by Business Interstate 15/90 for its entire length. The route travels from an incomplete interchange with I-15/90 through generally rural areas in western Butte. It interchanges with Excelsior Avenue before terminating. The entire route was improved to interstate standards during the 1960s, and was improved in 2005.

Interstate 115 begins at an interchange with Interstate 15 / Interstate 90. As a two-lane highway in both directions, I-115 heads east into downtown Butte. Before reaching exit 1, eastbound traffic makes a curve while westbound traffic goes to Interstate 15/90 without making such a curve, therefore that portion of I-115 contains a large median. Approximately 1 mile (1.6 km) from I-15/I-90, I-115 has its only interchange at Excelsior Avenue, which can be used to access the town of Walkerville. Excelsior Avenue is the only numbered exit along I-115, and the structure of the interchange directs motorists to stop and yield signs, as opposed to traffic signals for most exits in urban areas. I-115 ends at the overpass over Excelsior Avenue. It continues into Butte as I-15 Bus. / I-90 Bus..