West Lake (Chinese: 西湖; pinyin: Xī Hú) is a famous fresh water lake located in central Hangzhou, in Zhejiang province of eastern China.

The lake is divided by three causeways called Su Di (苏堤 , Bai Di (白堤, and Yanggong Di (杨公堤.

The name "West Lake" (Xi Hu) is also used by a large number of lakes in China and surrounding countries (with 800 West Lakes in China according to Lonely Planet). However, the lake in Hangzhou is the most famous of these, and the terms "West Lake" and "Xi Hu" generally refers to this lake.
In middle of the Tang Dynasty Zhenyuan era (785-804), poet Bai Juyi came to Hangzhou as governor. Already an accomplished poet, his deeds at Hangzhou made him a great governor. He realised that the farmland nearby depended on the water of West Lake, but due to negligence of former governors, the old dyke had collapsed, the water level of West Lake dried out, and the local farmers suffered severe drought. He ordered the construction of a stronger and taller dyke, with a dam to control the flow of water, and thus solved the drought problem. The livelihood of local people of Hangzhou improved over the following years. Now that Bai Juji had more leisure time to enjoy the beauty of West Lake, he visited West Lake almost every day. He ordered the construction of a causeway connecting the Broken Bridge with the Solitary Hill, to facilitate walking on foot, instead of depending on boat. Then he planted peach trees and willows trees along the dyke, making it a beautiful landmark of West Lake. This causeway was later named Bai Di Causeway in Bai Juyi's honour.

Over two hundred years later, in the beginning of Song Dynasty's Yuanyou era (1086-1094), another great poet, Su Shi (Su Dongpo), came to Hangzhou as governor. By that time, the farmers suffered drought again, due to overgrowth of the weeds at the bottom of the lake clogging the irrigation ducts. He ordered dredging of the lake and piled up all the mud into another causeway, in the style of Bai Causeway, but much wider and nearly three times as long, he also planted willow trees along its banks. This causeway was later named after him as the Su Causeway. There are six bridges along the 2.6 km Su Causeway. "Spring Dawn on the Su Causeway" is one of the attractions at the West Lake.