There have been nine business routes for Interstate 75 in the US state of Michigan. Numbered either Business Loop Interstate 75 (BL I-75) or Business Spur Interstate 75 (BS I-75) depending if they are a full business loop or a business spur, these highways are former routings of I-75's predecessor highways in the state. They were designated as I-75 was completed through the various areas of Michigan. 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. The former Saginaw business loop was once a part of US Highway 23 (US 23), as was most of the original Bay City business loop (that one has been converted into a business spur). The roadways that make up the business loops in West Branch and Roscommo