Tuttulikassak is one of several nunataks in the Melville Bay region of Greenland, where the Greenland ice sheet (Greenlandic: Sermersuaq) drains into the bay alongside its entire length apart from an occasional nunatak. Tuttulikassak is located on the mainland of Greenland in the northernmost part of Upernavik Archipelago, delimiting its northern end. To the east, Greenland icesheet drains southwards into Melville Bay via Hayes Glacier.
Before the administrative changes on 1 January 2009 in the country, the border between the former Upernavik Municipality and the former Qaanaaq Municipality ran approximately 7.7 km (4.8 mi) to the northwest of the nunatak, through Kjer Glacier. Since then, both municipalities and the entire coast of Melville Bay are part of the Qaasuitsup municipality, at 660,000 km2 (254,827.4 sq mi) the largest municipality in the world.