Business Loop I-15 - Butte

I-15/90 overlap for 7.65 miles across Butte and Silver Bow County. The pair combine in a rural area west of Rocker and split outside the Floral Park neighborhood of the city. A cosigned business route connects I-15/90 with Downtown Butte between Exits 124 and 127. Business Loop I-15/90 overlap with I-115 east to Iron Street, where they make a horseshoe shaped route north along a combination of Montana Street, Park Street and Arizona and Utah Avenues. Harrison Avenue (old U.S. 10/91) angle the routes southeast along a commercial boulevard to I-15/90 opposite the north end of MT 2.

The USGS Topo map shows Business Loops I-15/90 taking a shorter route from Interstate 115 and Iron Street east to Montana Street south and Front Street east. A pair of older shields stand at the Front Street intersection with Utah Avenue, where the two different alignments combine east to Harrison Avenue.

Updated July 31, 2026