Lake Ülemiste is the largest of the lakes surrounding Tallinn, Estonia. Ülemiste is the main part of the Tallinn water supply system, where most of the city gets its drinking water from. The lake is fed mostly by Kurna stream and Pirita River (through Vaskjala–Ülemiste canal).
Lennart Meri Tallinn Airport is located on the eastern shore of the lake and aircraft regularly take off and land over the lake. The airport maintains the necessary equipment ready to tow out in a short time any aircraft that crashes into the lake, as required by ICAO regulations.
The Tallinn Water Company, AS Tallinna Vesi, has a treatment plant on the North shore of the lake which supplies 90% of the water to the city. The remaining 10% comes from ground water wells which, whilst are not necessary as the lake can supply the entire city, are nevertheless maintained as a backup in case the lake ever became contaminated. Such a risk is not trivial considering the proximity of Tallinn Airport to the lake.
On 18 March 2010, a DHL Antonov An-26 aircraft made an emergency landing on the ice of Lake Ülemiste and 1,5 tons of fuel leaked into the water. Fortunately, all of the pollution was eventually removed, and none of the 6 crew members were injured.
Administratively Lake Ülemiste is part of Tallinn's central district Kesklinn, and constitutes Ülemistejärve subdistrict with its neighbouring forests., the population of the subdistrict is 203.