Lake Elmo Airport (FAA LID: 21D) is a public airport located just outside the city of Lake Elmo in Washington County, Minnesota, United States, about 12 miles east of the central business district of St. Paul. Although most airports in the United States use the same three-letter location identifier for the FAA and International Air Transport Association (IATA), this airport is assigned 21D by the FAA but has no designation from the IATA or ICAO. It is home to the Civil Air Patrol squadron NCR-MN-122.

It is included in the Federal Aviation Administration (FAA) National Plan of Integrated Airport Systems for 2021–2025 in which it is categorized as a regional general aviation facility.