- The Puget Lowland region is a wide low-lying area between the Cascade Range to the east and the Olympic Mountains to the west. The region extends from the San Juan Islands in the north to past the southern end of the Puget Sound. It is known for its scenic coastlines, bustling urban ports, and rich farmlands to the south. The natural resources and the geologic history of the Puget Sound and surrounding areas have helped to shape the history of the Washington state.