Lake Elmo is a lake in Washington County, Minnesota, in the United States, with a surface area of about 206 acres. It is partially within Lake Elmo Park Reserve, a regional park. The park also contains walking paths, camp grounds, playgrounds, and a swimming pond.
The lake was named after the 1866 novel St. Elmo by Augusta Jane Evans.
The nearby city Lake Elmo, Minnesota takes its name from the lake.