Velodrome Coffee Company
519 W Washington St, Marquette, MI
100% positive
Directions: Go into the coffee shop, turn left. There's a single restroom. It's a small shop so you'll be able to find it.
Comments: I'm not sure if you have to be a paying customer to use their bathroom. Not super accessible due to two steps into the coffee shop (although there may be a separate, stair-free entrance I am not aware of.)