Located in the southern part of Melville Bay, Kiatassuaq Island has an elongated shape, with an east–west orientation.

The island is separated from the Sanningassorsuaq Peninsula on the mainland of Greenland by the Ikerasaa Strait.

[3] The strait is split into two channels, with the small Millissua Island straddling the middle.

In the northeast, the Alison Bay separates the island from the Wandel Land nunatak.

Several other summits of the island ridge exceed 700 m (2,300 ft), from the massif overlooking Tasersuaq Lake in the east to the bastion over the Wilcox Head promontory in the west.