40 C.F.R. § 81.218
The Wabash Valley Intrastate Air Quality Control Region (Indiana) 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 area so delimited):
In the State of Indiana: Benton County, Carroll County, Cass County, Clay County, Clinton County, Fountain County, Fulton County, Howard County, Jasper County, Knox County, Miami County, Montgomery County, Newton County, Parke County, Pulaski County, Putnam County, Starke County, Sullivan County, Tippecanoe County, Tipton County, Vermillion County, Vigo County, Wabash County, Warren County, White County.
40 C.F.R. §81.218