Located in beautiful downtown Lake Nebagamon is Marker 151 about Evergreen Park Cottage Sanatorium.
According to this Camp Nebagamon site…
President Calvin Coolidge opted to spend the summer of 1928 at an estate along the Brule River. It housed his entourage of 60 soldiers, 14 servants, 10 secret servicemen, many of whom spent their free time in Lake Nebagamon. Coolidge established an office at Superior’s Central High School, and Douglas County spent more than $30,000 upgrading a dirt road into a modern gravel road now known as Highway B.
I think this is why this marker, located in front of what is apparently someone’s duplex, also has a “Coolidge Memorial Highway” marker nearby.