Mich. Comp. Laws § 123.63

Sec. 3. It shall be lawful for, and the several boards of supervisors are hereby authorized and empowered to make appropriations by way of contributing toward the improvement and maintenance of any such public parks, public zoological gardens, airports and landing fields, either owned or held in trust by any township, city or village within their respective counties or any adjoining county, or for any public parks, public zoological gardens, airports and landing fields, either owned or held in trust by any adjoining county, or for any public parks, zoological gardens, airports or landing fields, either owned or held in trust by 2 or more adjoining counties.