 Beyond Mahood Lake lies another separately classified area dubbed by Holland the Shuswap Highland which spans similar terrain across the North Thompson and Shuswap Lake-Adams River drainage basins, forming a similar upland-area buffer between the Thompson Plateau and the Monashee Mountains.A third area, the Okanagan Highland, extends from the southern end of the Shuswap Highland in the area of Vernon and Enderby in the northern Okanagan region into Washington State, and also abuts the Monashee Mountains .The boundary of the Quesnel Highland is not precisely defined in Holland, and in some interpretations it may be considered to be part of the Interior Plateau, as Holland defines it, or as a subrange of the Cariboo Mountains.