Mich. Comp. Laws § 123.583: Great lakes submerged lands; automatic annexation to cities and villages.

Sec. 3.

Whenever the boundary of any city or village in this state is the shore line of any of the Great Lakes or connecting waters, any filled-in submerged land which is attached to and an extension of the upland and which shall have been in existence for more than 15 years and any submerged islands not within any city or village but within 300 yards of the boundary of the city or village shall be included within the boundaries of the city or village without annexation proceedings and shall also be within the boundaries of the county and other units of government.