Cal. Code Regs. tit. 17 § 60104 : Public Health — Air Resources — Air Resources Board — Air Basins and Air Quality Standards — Description of California Air Basins — South Coast Air Basin

Beginning at the Riverside-San Diego County boundary and running north along the range line common to R. 4 E and R. 3 E; 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, 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 to the Riverside-San Bernardino County line.

Beginning at the San Bernardino-Riverside County boundary and running north along the range line common to R. 3 E and R. 2 E; then west along the township line common to T. 3 N and T. 2 N to the San Bernardino-Los Angeles County boundary.

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 Sections12,11, 10, 9, 8, 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, 17,18, 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 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.