40 C.F.R. § 81.241
The Southwestern Mountains-Augustine Plains Intrastate Air Quality Control Region (New Mexico) 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 New Mexico: Catron County, Socorro County.
Those portions of McKinley County lying east of the Continental Divide.
Those portions of Valencia County, excluding the Zuni and Ramah Navajo Indian Reservations, lying west of a line described as follows: Starting at the point at which the south boundary of Bernalillo County intersects with the section line between secs. 1 and 2 T. 7 N., R. 2 W.; thence south to the southern boundary of the Laguna Indian Reservation between secs. 35 and 36 T. 7 N., R. 2 W.; then southerly on section lines to the Socorro-Valencia County line at secs. 11, 12, 13, and 14, T. 5 N., R. 2 W.
40 C.F.R. §81.241