Michigan Compiled Laws, Chapter 125. Planning, Housing and Zoning § 125.3831

(a) For a county, the master plan may include planning in cooperation with the constituted authorities for incorporated areas in whole or to the extent to which, in the planning commission's judgment, they are related to the planning of the unincorporated area or of the county as a whole.

(b) For a township that on September 1, 2008 had a planning commission created under former 1931 PA 285,  2 or for a city or village, the planning jurisdiction may include any areas outside of the municipal boundaries that, in the planning commission's judgment, are related to the planning of the municipality.

(a) Make careful and comprehensive surveys and studies of present conditions and future growth within the planning jurisdiction with due regard to its relation to neighboring jurisdictions.

(b) Consult with representatives of adjacent local units of government in respect to their planning so that conflicts in master plans and zoning may be avoided.

(c) Cooperate with all departments of the state and federal governments, public transportation agencies, and other public agencies concerned with programs for economic, social, and physical development within the planning jurisdiction and seek the maximum coordination of the local unit of government's programs with these agencies.