Featured in this south-looking, low-oblique photograph is light blue, partially ice-covered Lake Sakakawea, the largest lake in North Dakota. Extending from Garrison Dam (not visible) to near Williston (not visible), Lake Sakakawea is approximately 200 miles (322 kilometers) long, has approximately 1600 miles (2576 kilometers) of shoreline, and provides irrigation for agriculture and recreation. Van Hook Arm is located within the Fort Berthold Indian Reservation. During the ice age, the Missouri River was the boundary between glaciation to the north and east and ice-free topography to the south and west. Visible are the Little Missouri River within the Bad Lands and the southwest portion of the Turtle Mountains.