40 CFR § 81.190 - Eastern Idaho Intrastate Air Quality Control Region.

The Eastern Idaho 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 Idaho: Bannock County, Bear Lake County, Bingham County, Bonneville County, Butte County, Caribou County, Clark County, Franklin County, Fremont County, Jefferson County, Madison County, Oneida County, Power County, Teton County.