40 CFR 81.133: Amarillo-Lubbock Intrastate Air Quality Control Region.

The Amarillo-Lubbock Intrastate Air Quality Control Region (Texas) 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 Texas: Armstrong County, Bailey County, Briscoe County, Carson County, Castro County, Childress County, Cochran County, Collingsworth County, Crosby County, Dallam County, Deaf Smith County, Dickens County, Donley County, Floyd County, Garza County, Gray County, Hale County, Hall County, Hansford County, Hartley County, Hemphill County, Hockley County, Hutchinson County, King County, Lamb County, Lipscomb County, Lubbock County, Lynn County, Moore County, Motley County, Ochiltree County, Oldham County, Parmer County, Potter County, Randall County, Roberts County, Sherman County, Swisher County, Terry County, Wheeler County, Yoakum County.