Interstate 115

Interstate 115
I-115 highlighted in red
Route information
Maintained by MDT
Length	1.194 mi[1] (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 Future Montana Highway System Interstate U.S. State Secondary ← I-94 MT 117 →

Interstate 115 (I-115) is a 1.194-mile-long (1.922 km) auxiliary Interstate Highway which connects I-15/I-90 to Butte in the U.S. state of Montana. The highway is concurrent with I-15 Bus./I-90 Bus. for its entire length. The highway travels from an incomplete interchange with I-15/I-90 through generally rural areas in western Butte. It also has an interchange with Excelsior Avenue before terminating. The entire route was improved to interstate standards during the 1960s, and was improved in 2005.

Route description

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..^[2][3]

History

Planning map for the Butte area freeways from 1955

The development of a freeway along the modern-day I-115 corridor was proposed in the 1950s. The 1955 General Location of National System of Interstate Highways, an early platform for what would become the Interstate Highway System, contained an inset of the proposed freeways in and around the city of Butte including an east-west freeway spur on the west side of the community.^[4] Designated as part of the Interstate Highway System around 1957, I-115's construction was funded by the federal government.^{[5][lower-alpha 1]}

Exit list

The entire route is in Silver Bow County.

Location	mi[8]	km	Exit	Destinations	Notes
​	0.000	0.000		I-15 south / I-90 west / I-15 Bus. begins / I-90 Bus. begins – Billings, Helena, Idaho Falls, Missoula	Exit 124 on I-15/I-90; no access to I-15 north/I-90 east
Butte	1.194	1.922	1	Excelsior Avenue – Walkerville
				I-15 Bus. north / I-90 Bus. east (Iron Street)	Continuation beyond Excelsior Ave.
1.000 mi = 1.609 km; 1.000 km = 0.621 mi       Incomplete access

References

External links

Route map:

• Interstate 115 - Montana