40 C.F.R. § 81.167
The Southeast Desert Intrastate Air Quality Control Region (California) 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 California: Imperial County.
Kern County-that portion of Kern County which lies east and south of a line described as follows: Beginning at the Kern-Los Angeles County boundary and running north and east along the northwest boundary of the Rancho La Liebre Land Grant to the point of intersection with the range line common to R. 15 W. and R. 16 W., San Bernardino Base and Meridian; then north along the range line to the northwest corner of Section 2, T. 32 S., R. 32 E., Mount Diablo Base and Meridian; then east along the township line common to T. 32 S. and T. 31 S.; then north along the range line common to R. 35 E. and R. 34 E.; then east along the township line common to T. 29 S. and T. 28 S.; then north along the range line common to R. 36 E. and R. 35 E.; then east along the township line common to T. 28 S. and T. 27 S.; then north along the range line common to R. 37 E. and R. 36 E. to the Kern-Tulare County boundary.
Los Angeles County-that portion of Los Angeles County which lies north and east of a line described as follows: Beginning at the Los Angeles-San Bernardino County boundary and running west along the township line common to T. 3 N. and T. 2 N., San Bernardino Base and Meridian; then north along the range line common to R. 8 W. and R. 9 W.; then west along the township line common to T. 4 N. and T. 3 N.; then north along the range line common to R. 12 W. and R. 13 W. to the southeast corner of Section 12, T. 5 N.; R. 13 W.; then west along the south boundaries of Sections 12, 11, 10, 9, 8, and 7, T. 5 N., R. 13 W. to the boundary of the Angeles National Forest which is collinear with the range line common to R. 13 W. and R. 14 W.; then north and west along the Angeles National Forest boundary to the point of intersection with the township line common to T. 7 N. and T. 6 N. (point is at the northwest corner of Section 4 in T. 6 N., R. 14 W.); then west along the township line common to T. 7 N. and T. 6 N.; then north along the range line common to R. 15 W. and R. 16 W. to the southeast corner of Section 13, T. 7 N., R. 16 W.; then along the south boundaries of Sections 13, 14, 15, 16, 17, and 18, T. 7 N., R. 16 W.; then north along the range line common to R. 16 W. and R. 17 W. to the north boundary of the Angeles National Forest (collinear with the township line common to T. 8 N. and T. 7 N.); then west and north along the Angeles National Forest boundary to the point of intersection with the south boundary of the Rancho La Liebre Land Grant; then west and north along this land grant boundary to the Los Angeles-Kern County boundary.
Riverside County-that portion of Riverside County which lies east of a line described as follows: Beginning at the Riverside-San Diego County boundary and running north along the range line common to R. 4 E. and R. 3 E., San Bernardino Base and Meridian; then east along the township line common to T. 8 S. and T. 7 S.; then north along the range line common to R. 5 E. and R. 4 E.; then west along the township line common to T. 6 S. and T. 7 S. to the southwest corner of Section 34, T. 6 S., R. 4 E.; then north along the west boundaries of Sections 34, 27, 22, 15, 10, and 3, T. 6 S., R. 4 E.; then west along the township line common to T. 5 S. and T. 6 S.; then north along the range line common to R. 4 E. and R. 3 E.; then west along the south boundaries of Sections 13, 14, 15, 16, 17, and 18, T. 5 S., R. 3 E.; then north along the range line common to R. 2 E. and R. 3 E.; then west along the township line common to T. 4 S. and T. 3 S. to the intersection with the southwest boundary of partial Section 31, T. 3 S., R. 1 W.; then northwest along that line to the intersection with the range line common to R. 2 W. and R. 1 W.; then north to the Riverside-San Bernardino County line.
San Bernardino County-that portion of San Bernardino County which lies east and north of a line described as follows: Beginning at the San Bernardino-Riverside County boundary and running north along the range line common to R. 3 E. and R. 2 E., San Bernardino Base and Meridian; then west along the township line common to T. 3 N. and T. 2 N. to the San Bernardino-Los Angeles County boundary.
40 C.F.R. §81.167