(MI-81-66) N. of Ann Arbor, Ann Arbor Township, Washtenaw County, MI. Whitmore Lake Rd. N. 0.75 miles from jct with Bus.US23/MI14 on the N. side of Ann Arbor, NW on Barton North Dr. 0.65 miles, S. (left) on Hillspur Rd. 0.2 miles to the turret on the E. side of the road at 521. (N42 19.096 W83 45.523) Photo by Mark Comstock 6-7-21.