Michigan Compiled Laws, Chapter 280. Drain Code of 1956 § 280.461

(a) “State” means this state.

(b) “Public corporation” includes this state, counties, cities, villages, townships, metropolitan districts and authorities created by or pursuant to state statutes.

(c) “Agencies” includes those officers, boards, commissions and other bodies created by public corporations or by the federal government, which are authorized to act in their own names.

(d) “County drain” means any drain, irrespective of size, carrying drainage water or sewage or both originating in 1 county, and includes drains located, established and constructed by a county drain commissioner or drainage board, by a city, village or township. The finding of the drainage board that all drain water and sewage does originate in 1 county shall be final. In making such determination, the drainage board may disregard any drainage from another county which it deems to be inconsequential.