Hamburger Hallig, Tidal island in North Frisia, Germany

Hamburger Hallig is a dikeless peninsula on the west coast of Nordfriesland, connected to the mainland by a causeway built in 1866/67. It has three warften (artificial mounds): the main Warft, four kilometres west of the Sönke-Nissen-Koog sea dike, holds the Hallig Krog inn, a National Park Service outpost and the Watt-Werkstatt; the Kuhberg lies 300 metres south; the Schafberg, with the NABU station, is two kilometres east. The main Warft's low white buildings have dark grey pitched roofs and a taller gabled section with a large rectangular opening.

The island was initially developed in the early 17th century by Hamburg merchants who built dikes, but the Burchardi Flood of 1634 destroyed these defenses. Following that catastrophe, the island was repeatedly resettled and rebuilt as its inhabitants continuously adapted their structures to natural forces.

The name recalls Hamburg merchants Rudolf and Arnold Amsinck, who obtained dike rights here in 1624; the "Hamburger Haus" on the main Warft sheltered Strand residents during the 1634 Burchardi Flood. The Hallig Krog inn on that mound serves guests from Easter to 31 October, and the Watt-Werkstatt of the National Park Service holds an exhibition and laboratory. The Schafberg mound, halfway to the mainland, carries the NABU station named Claus-Jürgen Reitmann-Haus.

The causeway from the mainland has been passable since 1901 and leads four kilometres west to the main Warft. The Hallig Krog inn there is open from Easter (at the latest 1 April) until 31 October. The Schafberg with the NABU station lies about halfway along the causeway, in the foreland rather than on the Hallig itself.

The causeway built in 1866/67 interrupted the tidal currents and greatly accelerated sedimentation on both sides, an experience that shaped later land reclamation in North Frisia. The dam has been passable since 1901, and the western shore is now secured against further land loss.