Dock #73. No existing dock. Ready for your custom dock. Harbortown Marina (also known as Harbortown Condominium Marina Association) is a private condominium marina located along the Au Gres River in Au Gres, Michigan, with direct access to Lake Huron/Saginaw Bay. The address is: 149 W Huron Rd, Au Gres, MI 48703 This is a private facility with individually owned boat slips, often featuring amenities like a clubhouse, pool, and bathhouse. It's distinct from public or other marinas in the area, such as Point Au Gres Marina or the Au Gres Yacht Club.