| Sammisoq | |
| Native Name: | Christian IV Ø |
| Native Name Link: | Danish language |
| Nickname: | Christian IV Island |
| Image Map Size: | 270px |
| Image Map Caption: | Map of Sammisoq |
| Pushpin Map: | Greenland Southern Tip#Greenland Southern#Greenland |
| Pushpin Label: | Sammisoq |
| Pushpin Map Caption: | Location of Sammisoq in Greenland |
| Coordinates: | 60.0528°N -43.6867°W |
| Location: | Irminger Sea |
| Archipelago: | Nunap Isua Archipelago |
| Waterbody: | North Atlantic Ocean |
| Area Km2: | 659 |
| Rank: | 11th largest in Greenland |
| Length Km: | 60 |
| Coastline M: | --> |
| Elevation M: | 1546 |
| Elevation Footnotes: | [1] |
| Highest Mount: | Niaqornaq |
| Country: | Greenland |
| Country Admin Divisions Title: | Municipality |
| Country Admin Divisions: | Kujalleq |
| Country Admin Divisions Title 1: | Weather station |
| Country Admin Divisions 1: | Ikerasassuaq |
| Country Area M2: | or |
| Country Area Ha: | --> |
| Population: | 0 |
| Population As Of: | 2021 |
| Density Km2: | 0 |
| Ethnic Groups: | none |
Sammisoq (old spelling Sangmissoq, Danish: Christian IV Ø; English traditional:Christian IV Island) is an island in the Kujalleq municipality in southern Greenland, located northeast of Uummannarsuaq cape. It is the largest island of the Cape Farewell Archipelago (Nunap Isua).
Its area is 6590NaN0 and at its largest length is 600NaN0. It is separated from mainland Greenland to the north by the narrow Prince Christian Sound. The island has glaciers in the south and in the west. Its coast is deeply indented and its southern part is almost separated from the main island by two narrow inlets.[2] To the south lies Itilleq Island and to the west Annikitsoq, both part of the same group.
There is one settlement, Ikerasassuaq, also called Prince Christian Sound, Prins Christian Sund, or Bluie East One. It is a weather station and has no permanent population.
Sammisoq is mountainous and Niaqornaq, its highest point, is 1546 m above sea level.[3] It is an ultra prominent peak, meaning a journey to any higher mountain involves descending more than 1500 m down before going up again, in this case down to sea level.