40 C.F.R. § 81.98
The Burlington-Keokuk Interstate Air Quality Control Region (Illinois-Iowa) is revised to consist 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 Illinois: Fulton County, Hancock County, Henderson County, Knox County, McDonough County, Mason County, Peoria County, Tazewell County, Warren County, Woodford County.
In the State of Iowa: Des Moines County, Lee County.
Note: For purposes of identification, the regions are referred to by Illinois authorities as follows:
Sec.
481.14 Metropolitan Chicago Interstate Air Quality Control Region: Region III.
481.262 North Central Illinois Intrastate Air Quality Control Region: Region V.
481.98 Burlington-Keokuk Interstate Air Quality Control Region: Region VI.
481.263 East Central Illinois Intrastate Air Quality Control Region: Region VII.
481.264 West Central Illinois Intrastate Air Quality Control Region: Region VIII.
481.18 Metropolitan St. Louis Interstate Air Quality Control Region: Region IX.
481.265 Southeast Illinois Intrastate Air Quality Control Region: Region X.
481.69 Paducah-Cairo Interstate Air Quality Control Region: Region XI.
40 C.F.R. §81.98