West Lake is located west of Hangzhou City. There are dozens of lakes called West Lake worldwide, but "West Lake" usually refers to the west lake in Hangzhou. It is surrounded by mountains on three sides, with an area of around 6.5 square kilometers. The distance from north to south is about 3.2 kilometers, and east to west, 2.8 kilometers. The circumference is around 15 kilometers. The average depth of West Lake is 2.27 meters, and the capacity is about 14,290,000 cubic meters. The lake is divided by Gu Shan, Bai, Su and Yanggong Causeways into five areas. Ordered by their areas, they are Outer West Lake (外西湖), West Inner Lake (西里湖, or 后西湖, or 后湖), North Inner Lake (北里湖 or 里西湖), Little South Lake (小南湖 or 南湖) and Yue Lake (岳湖). "Outer West Lake" is the largest. "Gu Shan" or Gu Hill is the largest natural island in the lake. Su & Bai Causeways run cross the lake. Three small man-made islands, "Xiao Ying Zhou" (小瀛洲), "Hu Xing Ting" (湖心亭), "Ruan Gong Dun" (阮公墩), lie in the center of Outer West Lake. Thus, the basic layout is "one hill, two causeways, three islands, and five lakes".