Mamry is a lake

Lake

A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...

 in the Masurian Lake District of Poland

Poland

Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...

's Warmia-Mazury Province. It is the second largest lake in Poland, with an area of 104 km.² Maximum depth is 44 m, average is 11 m.

It actually comprises six connected lakes: Mamry, Kirsajty, Kisajno, Dargin, Święcajty and Dobskie. Mamry features 33 islands, totalling 213 hectare

Hectare

The hectare is a metric unit of area defined as 10,000 square metres , and primarily used in the measurement of land. In 1795, when the metric system was introduced, the are was defined as being 100 square metres and the hectare was thus 100 ares or 1/100 km2...

s, some of which are ornithological reserves.

Lake Mamry is a popular tourist destination. It is connected to the Pregolya

Pregolya

The Pregolya or Pregola is a river in the Russian Kaliningrad Oblast exclave.It starts as a confluence of the Instruch and the Angrapa and drains into the Baltic Sea through Vistula Lagoon. Its length under the name of Pregolya is 123 km, 292 km including the Angrapa. The basin has an...

 and the Baltic Sea

Baltic Sea

The Baltic Sea is a brackish mediterranean sea located in Northern Europe, from 53°N to 66°N latitude and from 20°E to 26°E longitude. It is bounded by the Scandinavian Peninsula, the mainland of Europe, and the Danish islands. It drains into the Kattegat by way of the Øresund, the Great Belt and...

 by the disused Masurian Canal

Masurian Canal

The Masurian Canal is a canal connecting the Lava River in Kaliningrad Oblast of Russia and Lake Mamry, one of the Masurian Lakes in Poland. It was constructed between 1764 and 1776 under the auspices of Johann Friedrich Domhardt. It was modernised on several occasions, most importantly in the...

.