Michigan Highway 15 is a north-south highway that parallels Interstate 75 to the east by five to twelve miles, between Bay City and a town north of Pontiac called Clarkston. It kind of serves as a northward extension of the corridor started by US Route 24, though of course, Michigan Highway 24 does something similar; Michigan Highway 24 lies even farther east as the next north-south highway. While Interstate 75 lies to the west of Michigan Highway 15, connecting to Flint and Saginaw, this Michigan Highway stays east of those locales. Instead, it serves small towns like Davison and Vassar. The southern end of Michigan Highway 15 is at a US Route 24 that's barreling northwestward for its northern terminus in Clarkston. The northern end is on the east side of Bay City, at an east-west portion of Michigan Highway 25. The route, especially the northern half, has a northwest-southeast angle to it.
My photo of Michigan Highway 15 comes from its junction with Michigan Highway 81, which runs west from this junction to Saginaw. The diagonal intersection home to the northbound trailblazer in this photo is near the town of Reese. This photo was taken in April 2021 during my trip around the Michigan Thumb and Metro Detroit.
Here are some more photos along Michigan Highway 15:
Southbound Michigan Highway 15 at Michigan Highway 81.
Michigan Highway 15 southbound at Michigan Highway 83, north of Frankenmuth.