Sobieszewo Island (German: Bohnsack) is an island on the Baltic sea, between the Gdańsk Bay and the delta of Vistula river. The island is part of the territory of the city of Gdańsk, Poland. Area: 34.3 km² Population: 3,570 people. Density: 104 people/km² The northern border of the island is the waters of Gdańsk Bay, while its southern border is a branch of the Vistula river, called Leniwka. The western border was created in 1840 during the flooding and creation of a new mouth of Vistula called Śmiała Wisła. The eastern border was dug in 1895 as a new, artificially created mouth of Vistula, called Przekop Wisły. In Górki Wschodnie is located Birds reservation and the center of the researches on birds. Sobieszewo Island is one of the 34 quarters of Gdańsk.