Okauchee Lake is a census-designated place in Waukesha County, Wisconsin, United States. The population was 5,094 at the 2020 census. Okauchee Lake is located in the town of Oconomowoc. Okauchee Lake is located at 43°7′10″N 88°26′23″W / 43.11944°N 88.43972°W.