The seed potato isolation district consists of that area of Whatcom County lying within the following boundaries:

On the west the boundary follows Georgia Straight from the Canadian border south to Slater Road.

On the north the boundary follows the Canadian border from Georgia Straight easterly to South Pass Road.

On the east the boundary follows South Pass Rd. southwesterly to the point where the eastern edge of Range 4 East intersects South Pass Road, then south along the eastern boundary of Range 4 East to the Nooksack River (south of the town of Deming).

On the south the boundary follows the Nooksack River northwesterly to the City of Everson, south from Everson on Mission Road to Smith Road, westerly on Smith Rd to Interstate 5, southeasterly on Interstate 5 to Slater Road, westerly on Slater Road to Rural Ave., southwesterly on Rural Ave. to Marine Dr., westerly on Marine Dr. to Ferndale Rd., northerly on Ferndale Rd. to Slater then westerly on Slater to Georgia Straight.