The Alps are usually divided into two main parts, the Western Alps and Eastern Alps, whose division is along the Rhine from Lake Constance to the Splügen Pass. The western ranges occupy the greatest part of Switzerland while the more numerous eastern ranges are much smaller and are all situated in the canton of Graubünden. The latter is part of the Central Eastern Alps, except the Ortler Alps which belong to the Southern Limestone Alps. The Pennine, Bernese and Bernina Range are the highest ranges of the country, they contain respectively 38, 9 and 1 summit over 4000 meters. The lowest range is the Appenzell Alps culminating at 2,500 meters.