(a) Name. The name of the viticultural area described in this section is “Spring Mountain District.”

(b) Approved maps. The appropriate maps for determining the boundary of the Spring Mountain District viticultural area are four U.S.G.S. 7.5 minute series topographical maps of the 1:24000 scale. They are titled:

(1) “Kenwood, Calif.,” 1954 (photorevised 1980).

(2) “Rutherford, Calif.,” 1951 (photorevised 1968).

(3) “St. Helena, Calif.,” 1960 (photorevised 1980).

(4) “Calistoga, Calif.,” 1958 (photorevised 1980).

(c) Boundary. The Spring Mountain District viticultural area is located in Napa County, California, within the Napa Valley viticultural area. The boundary is as follows:

(1) Beginning on the Calistoga quadrangle map at the Napa-Sonoma county line at the boundary line between sections 18 and 19 in T8N/R6W.

(2) Then east along the boundary line between sections 18 and 19 for approximately 3/4 of a mile to its intersection with Ritchie Creek at the boundary line between sections 17 and 20.

(3) Then northeast along Ritchie Creek approximately 2 miles, to the 400 foot contour line in the northeast corner in section 16 of T8N/R6W.

(4) Then along the 400 foot contour line in a northeast then generally southeast direction, through the St. Helena and Rutherford quadrangle maps, approximately 9 miles, past the town of St. Helena to the point where it intersects Sulphur Creek in Sulphur Canyon, in the northwest corner of section 2 in T7N/R6W.

(5) Then west along Sulfur Creek (onto the Kenwood quadrangle map) and south to the point where it first divides into two intermittent streams in section 3 in T7N/R6W.

(6) Then south along the intermittent stream approximately 1.5 miles to the point where it intersects the 2,360 foot contour line in section 10 in T7N/R6W.

(7) Then southwest in a straight line, approximately .10 mile, to the unnamed peak (elevation 2600 feet) at the boundary line between Napa and Sonoma Counties.

(8) Then in a generally northwest direction along the Napa-Sonoma county line, through sections 10, 9, 4, 5, 32, 33, 32, 29, 20, and 19, to the beginning point on the Calistoga quadrangle map at the boundary between sections 18 and 19 in T8N/R6W.