The southern end of the valley begins elevated regions, with the Mohave Mountains directly south, and Dutch Flat, east of the Mohave Mountains, which drains northwest into Sacramento Wash. The southeast of the valley meets the outfall of Sacramento Wash, and associated drainage plains; Sacramento Valley itself is mostly east and south of the Black Mesa section at the south of the Black Mountains (Arizona); the Sacramento Wash turns due west, and follows Interstate 40 in Arizona as it turns west and parallels the wash to meet Needles at the Colorado River; it is also the southern drainage outfall point into the Topock Marsh, at Topock, eastern shore of the Colorado River, in the southeast valley. Other washes drain through the eastern Mohave Valley plains and foothills into the Topock Marsh from the southwest of the Black Mountains, the extensive range which goes north to Lake Mead.