Lugu Lake—also known as Yongning Hai, Zuosuo Hai, Lede Hai, Luoshui Haizi, or Xienami—is a freshwater highland lake situated in the People's Republic of China, straddling the border between the northern part of Yunnan Province and the southwestern part of Sichuan Province. It lies between Yanyuan County in the Liangshan Yi Autonomous Prefecture (Sichuan Province) and Ninglang Yi Autonomous County in Lijiang City (Yunnan Province). The lake features an expansive wetland area filled with aquatic vegetation in its southeastern section, known as "Cao Hai" (Grass Sea), while the broader, open expanse of water is called "Liang Hai" (Bright Sea). The lake sits at an elevation of 2,690 meters above sea level and covers an area of 48.45 square kilometers.