The Northwestern Oklahoma 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 area so delimited):
In the State of Oklahoma: Alfalfa County, Beaver County, Blaine County, Cimarron County, Custer County, Dewey County, Ellis County, Harper County, Major County, Roger Mills County, Texas County, Woods County, Woodward County.