(a) Name. The name of the viticultural area described in this section is “Lewis-Clark Valley”. For purposes of part 4 of this chapter, “Lewis-Clark Valley” is a term of viticultural significance.

(b) Approved maps. The three United States Geographical Survey (USGS) 1:100,000 (metric) scale topographic maps used to determine the boundary of the Lewis-Clark Valley viticultural area are titled:

(1) Clarkston, Wash.-Idaho-Oregon, 1981;

(2) Orofino, Idaho-Washington, 1981; and

(3) Potlatch, Idaho, 1981.

(c) Boundary. The Lewis-Clark Valley viticultural area is located in Nez Perce, Lewis, Clearwater, and Latah Counties, Idaho, and Asotin, Garfield, and Whitman Counties, Washington. The boundary of the Lewis-Clark Valley viticultural area is as follows:

(1) The beginning point is located on the Clarkston map in Washington State along the Garfield-Asotin County line at the southwest corner of section 18, T11N/R45E. From the beginning point, proceed east along the southern boundary line of section 18, crossing over the Snake River, and continue along the southern boundary line of section 17, T11N/R45E, to the southeast corner of section 17; then

(2) Proceed north along the eastern boundary line of section 17 to the 600-meter elevation contour; then

(3) Proceed generally east-northeast along the meandering 600-meter elevation contour, crossing into Idaho and onto the Orofino map, then continue to follow the elevation contour in an overall clockwise direction, crossing back and forth between the Orofino and Clarkston maps and finally onto the Potlatch map, and then continuing to follow the 600-meter elevation contour in a clockwise direction to the elevation contour's intersection with the southern boundary line of section 1, T37N/R1W, on the Potlatch map, north of the Nez Perce Indian Reservation boundary and west of the Dworshak Reservoir (North Fork of the Clearwater River) in Clearwater County, Idaho; then

(4) Cross the Dworshak Reservoir (North Fork of the Clearwater River) by proceeding east along the southern boundary line of section 1, T37N/R1E, to the southeastern corner of section 1; then by proceeding north along the eastern boundary line of section 1 to the southwest corner of section 6, T37N/R2E; and then by proceeding east along the southern boundary line of section 6 to the 600-meter elevation contour; then

(5) Proceed generally east initially, then generally south, and then generally southeast along the meandering 600-meter elevation contour, crossing onto the Orofino map, and then continuing to follow the elevation contour in an overall clockwise direction, crossing back and forth between the Orofino and Potlatch maps, to the eastern boundary of section 13, T35N/R2E, on the Orofino map in Clearwater County, Idaho; then

(6) Proceed south along the eastern boundary of section 13, T35N/R2E, to the southeastern corner of section 13, T35N/R2E, northeast of Lolo Creek; then

(7) Proceed west along the southern boundary line of section 13, T35N/R2E, to the Clearwater-Idaho County line in the middle of Lolo Creek; then

(8) Proceed generally west-northwest along the Clearwater-Idaho County line (concurrent with Lolo Creek) to the Lewis County line at the confluence of Lolo Creek and the Clearwater River; then

(9) Proceed generally south along the Lewis-Idaho County line (concurrent with the Clearwater River) to the northern boundary line of section 23, T35N/R2E; then

(10) Proceed west along the northern boundary line of section 23, T35N/R2E, to the 600-meter elevation contour; then

(11) Proceed generally northwest along the meandering 600-meter elevation contour, crossing onto the Potlatch map and then back onto the Orofino map and continuing generally southwest along the 600-meter elevation contour to the common T32N/T31N township boundary line along the southern boundary line of section 35, T32N/R5W, south of Chimney Creek (a tributary of the Snake River) in Nez Perce County, Idaho; then

(12) Proceed west along the common T32N/T31N township boundary line, crossing Chimney Creek, to the Idaho-Washington State line (concurrent with the Nez Perce-Asotin County line) at the center of the Snake River; then

(13) Proceed generally southeast along the Idaho-Washington State line in the Snake River to the northern boundary line of section 29, T31N/R5W; then

(14) Proceed west along the northern boundary line of section 29, T31N/R5W, to the 600-meter elevation contour, northeast of Lime Hill in Asotin County, Washington; then

(15) Proceed generally west and then generally south-southwest along the meandering 600-meter elevation contour to the southern boundary line of section 25, T7N/R46E; then

(16) Proceed west along the southern boundary lines of section 25 and 26, crossing onto the Clarkston map, and continuing along the southern boundary lines of section 26 to the 600-meter elevation contour west of Joseph Creek; then

(17) Proceed southeast along the meandering 600-meter elevation contour to the western boundary line of section 34, T7N/R46E; then

(18) Proceed north along the western boundary lines of sections 34 and 27, T7N/R46E, crossing over the Grande Ronde River, to the 600-meter elevation contour; then

(19) Proceed generally northeast along the meandering 600-meter elevation contour and continue along the 600-meter elevation contour in a clockwise direction, crossing back and forth between the Clarkston and Orofino maps, until, on the Clarkston map, the 600-meter elevation line intersects the Garfield-Asotin County line for the third time along the western boundary of section 19, T11N/R45E; and then

(20) Proceed north along the Garfield-Asotin County line, returning to the beginning point.