The business loop in Pontiac runs through that city's downtown along a section of Woodward Avenue and a segment of roadway formerly used by M-24.

In Northern Michigan, the Grayling and Gaylord BL I-75s were part of US 27, and the two business routes in St. Ignace and Sault Ste.

The Woodward Avenue Loop encircles downtown Pontiac, and it is crossed by the eastbound direction of M-59 running on Huron Street.

Lapeer Road continues as a six-lane, divided roadway to the ramps of a double trumpet interchange, where the BL I-75 designation ends.

After the change, US 10 turned south from Dixie Highway onto Telegraph and then east onto Square Lake to connect back to Woodward.

[18][19] In 1985, the Michigan Department of Transportation (MDOT) received permission from the American Association of State Highway and Transportation Officials to truncate US 10 to Bay City,[20] and when the change was made the following year, US 24 replaced US 10 on Telegraph Road north of Square Lake Road, and Bus.

About three blocks farther west, BL I-75 split from M-46 to follow Genesee Avenue northwesterly into the downtown area.

[33][34] In 1953, the initial eastern bypass of Saginaw was built as a two-lane highway, and the former routing through downtown was redesignated Bus.

[35][36] This bypass was upgraded in 1961 to a full freeway as part of I-75/US 23, and the business loop through downtown was redesignated BL I-75.

The segments of the business loop that were concurrent with M-13, M-46 or M-81 remained part of those state highways, but the rest of BL I-75 was returned to local control.

BS I-75 runs concurrently along M-25, and for about the first 1+1⁄3 miles (2.1 km), the spur is a four-lane freeway bounded by residential subdivisions on either side.

Just three blocks east of the river, BS I-75 ends at the intersections with M-84 (Washington Avenue) in downtown Bay City.

[8] When the United States Numbered Highway System was created in 1926, M-10 became part of US 23, although it was routed on the western side of the Saginaw River.

[33][34] By early 1941, US 23 was rerouted to cross the Saginaw River on the southern side of Bay City, and the former routing along Washington Avenue and Midland Street through downtown was renumbered Bus.

From that interchange, BL I-75 runs northward along Cook Road in Horton and West Branch townships past an outlet mall.

Starting at exit 239 along I-75, the business loop runs concurrently with M-18 northward along the two-lane Roscommon Road through rural Northern Michigan woodlands.

From this interchange, the business loop runs northward as a five-lane divided roadway through a commercial area and past the Grayling Golf Club.

BL I-75/M-72 narrows to three lanes and crosses the Au Sable River and runs for about 3⁄4 mile (1.2 km) before intersecting Lake Street in downtown Grayling.

[67] It would start at exit 310 on I-75 in Tuscarora Township and follow M-68 across the North Central State Trail near the Sturgeon River.

North of the club, the roadway runs through forest land and past the occasional business before meeting I-75 at exit 310.

In November 1960, sections of I-75 freeway opened from Indian River north to the southern Mackinac Bridge approaches in Mackinaw City,[69] By the end of the following year, I-75 was completed between Gaylord and Grayling.

[72] At that time, South Straits Highway through Indian River between M-68 and M-27 was turned over to local control as a county road.

[75] A business loop for Indian River was first proposed to the Cheboygan County Road Commission (CCRC) in June 2015.

[76] The CCRC held a community forum in June 2016, and many local residents and businesses supported the designation at the time.

[77] The Tuscarora Township Board and Downtown Development Authority have expressed interesting in paying for the necessary signage should MDOT and the CCRC move forward to apply for the designation from the American Association of State Highway and Transportation Officials.

BL I-75 has three lanes and runs along the lakefront past the marina and docks for Mackinac Island ferry services.

North of the point, BL I-75 follows the Lake Huron shoreline past the Mackinac County Airport.

The business loop intersects County Road H-63 (Mackinac Trail) and comes to an end near Castle Rock at exit 348 on I-75 in St. Ignace Township.

The spur runs through commercial areas and intersects the northern end of M-129 (Dixie Highway) before turning due north along Ashmun Street near the Sault Ste.

BS I-75 turns northeasterly past Easterday Avenue and runs to the east of the campus of Lake Superior State University, crossing the Edison Sault Power Canal.