The Grand Mesa Intrastate Air Quality Control Region (Colorado) 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 Colorado: Delta County, Eagle County, Garfield County, Gunnison County, Hinsdale County, Mesa County, Montrose County, Ouray County, Pitkin County, San Miguel County, Summit County.