Rusałka, until 1945 known as Westendsee (West End Lake), is a dam lake in Szczecin, Poland located in northern part of Jan Kasprowicz Park.

Rusałka was formed druign the Middle Ages when the Osówka stream present in the area was dammed during the construction of nearby gristmills, one called Malzmühle the east and one, known as Lübsche Mühle, on the west side of the modern lake.

The modern shape of the lake was formed in 1885 after the waters of Osówka were dammed again.

[1] The inhabitants of Stettin (now Szczecin, Poland) could sail on the lake with rented boats and visit Haus am Westendsee coffeehouse, that operated at the prior site of the Malzmühle gristmill.

In 2008 a local catering company bought the location, with the intention of building a new coffeehouse on the foundations of Haus am Westendsee however the plans were canceled and the location was sold in 2009.