洪泽湖，中国五大淡水湖之一，位于淮河下游、江苏省淮安市西北部，是未来“南水北调”工程东线部分的过水信道。在正常水位12.5米时，水面面积为1597平方公里，平均水深1.9米，最大水深4.5米，容积30.4亿立方米。湖泊长度65公里，平均宽度24.4公里，汛期或大水年份水位可高到15.5米，面积扩大到3,500平方公里。近年加固了洪泽湖大堤，防洪标准提高到16公尺。洪泽湖东北——西南向为拦洪人工石坝，其余为天然湖岸，全源水域由成子湖湾、溧河湖湾、淮河湖湾三大湖湾组成。洪泽湖为一"悬湖"，湖底高出东部里下河平原4～8米。

Hongze Lake (Chinese:洪泽湖; pinyin:Hóngzé Hú) is located in Jiangsu Province, China and is encompassed by the prefecture-level cities Suqian (Sihong County and Siyang County) and Huai'an (Xuyi County and Hongze County).

Lake Hongze is the fourth largest freshwater lake in China. Lake Hongze has quadrupled in size since the 12th century.