Hasselwerder, Islet in Reinickendorf, Berlin, Germany

Hasselwerder is the northernmost island in the Tegeler See, part of Berlin's Reinickendorf district. It measures about 300 metres long and 60 metres wide, with an area of 12,321 square metres. A landing jetty on its northeast side serves the island.

Hasselwerder belonged to the Tegel estate from 1755; in 1766 the estate and its castle, with the island, passed to the von Humboldt family, whose descendants still own it. From 1911 the estate administration ran a bathing establishment on the island, operated by changing tenants with interruptions until 1954. In 1946 the shipowner Walter Haupt leased the island as a home port for his ships and lived there himself.

From 1911 the estate administration ran a bathing establishment on Hasselwerder, leased by various operators and open with interruptions until 1954. The shipowner Walter Haupt leased the island in 1946, used it as a home port for his ships and lived there himself; in 1950 he converted an old utility building into the inn Wirtshaus Hasselwerder/Zum Insulaner. After the bathing establishment closed he rented pitches for tents and later allotment huts to summer guests, several of which still stand.

Hasselwerder is not open to visitors; it is private property of the von Humboldt family estate and lies within the LSG-2C Inseln im Tegeler See protected landscape. The island has a landing jetty on its northeast side, but bank reinforcement and the building of boat jetties require special permits from the nature conservation authority. The islet is seen from the shore or from boats on the Tegeler See.

Since 1960 Hasselwerder has belonged to the LSG-2C Inseln im Tegeler See landscape protection area, so building jetties or reinforcing the banks requires a special permit from the nature conservation authority. The island's only landing stage lies on its northeast side.