(MI-74-10) NW of St. Clair, Columbus Township, St. Clair County, MI. Clinton Av. (becomes Rattle Run Rd.) W. (curves NW) 6.8 miles from jct with Riverside Av. in St. Clair, SW on Gratiot Av. 1.2 miles to the turret on the NW side of the road at 7582. (N42 51.454 W82 37.237) Photo by Mark Comstock 8-12-22.