(a) Name. The name of the viticultural area described in this section is “Mendocino Ridge.”

(b) Approved maps. The appropriate maps for determining the boundary of the Mendocino Ridge viticultural area are four 1:62,500 scale U.S.G.S. topographical maps. They are titled:

(1) Ornbaun Valley Quadrangle, California, 15 minute series topographic map, 1960;

(2) Navarro Quadrangle, California, 15 minute series topographic map, 1961;

(3) Point Arena Quadrangle, California, 15 minute series topographic map, 1960;

(4) Boonville Quadrangle, California, 15 minute series topographic map, 1959.

(c) Boundary. The Mendocino Ridge viticultural area is located within Mendocino County, California. Within the boundary description that follows, the viticultural area starts at the 1200 foot elevation (contour line) and encompasses all areas at or above the 1200 foot elevation line. The boundaries of the Mendocino Ridge viticultural area, using landmarks and points of reference found on appropriate U.S.G.S. maps, follow.

(1) Beginning at the Mendocino/Sonoma County line at the mouth of the Gualala River, where the Gualala River empties into the Pacific Ocean, in section 27 of Township 11 North (T11N), Range 5 West (R5W), located in the southeastern portion of U.S.G.S. 15 minute series map, “Point Arena, California;”

(2) Then following the Mendocino/Sonoma County line eastward to the southeast corner of section 8 in T11N/R13W, on the U.S.G.S. 15 minute map, “Ornbaun Valley, California;”

(3) Then from the southeast corner of section 8 in T11N/R13W directly north approximately 3 + miles to the southwest corner of section 9 in T12N/R13W;

(4) Then proceeding in a straight line in a northwesterly direction to the southwestern corner of section 14 in T13N/R14W;

(5) Then directly north along the western line of section 14 in T13N/R14W to a point on the western line of section 14 approximately 1/4 from the top where the Anderson Valley viticultural area boundary intersects the western line of section 14 in T13N/R14W;

(6) Then in a straight line, in a northwesterly direction, to the intersection of an unnamed creek and the south section line of section 14, T14N/R15W, on the U.S.G.S. 15 minute series map, “Boonville, California;”

(7) Then in a westerly direction along the south section lines of sections 14 and 15 in T14N/R15W to the southwest corner of section 15, T14N/R15W, on the U.S.G.S. 15 minute series map, “Navarro, California;”

(8) Then in a northerly direction along the western section lines of sections 15, 10, and 3 in T14N/R15W in a straight line to the intersection of the Navarro River on the western section line of section 3 in T14N/R15W;

(9) Then in a northwesterly direction along the Navarro River to the mouth of the river where it meets the Pacific Ocean in section 5 of T15N/R17W;

(10) Then in a southern direction along the Mendocino County coastline to the Mendocino/Sonoma County line to the beginning point at the mouth of the Gualala River in section 27 of T11N/R15W, on the U.S.G.S. 15 minute series map, “Point Arena, California.”