what county is greenbush in
Find Greenbush Activities: Play | Stay | Plan | Shop | Events | Deals. A historic and beautiful spot in eastern Alcona County. Greenbush is an unincorporated community on US 23 a few miles south of Harrisville on the shores of Lake Huron. In 1847-48, Crosier Davison, of Detroit, built a fishery and cooperage at what was then known as the Sliding Banks of the Au Sable.