The South Central Michigan Intrastate Air Quality Control Region consists of the territorial area encompassed by the boundaries of the following jurisdictions or described area (including the territorial area of all municipalities (as defined in section 302(f) of the Clean Air Act, 42 U.S.C. 1857h(f)) geographically located within the outermost boundaries of the areas so delimited):
In the State of Michigan: Barry County, Branch County, Calhoun County, Clinton County, Eaton County, Hillsdale County, Ingham County, Jackson County, Kalamazoo County, Lenawee County, Livingston County, St. Joseph County, Washtenaw County.