Tunu, originally Østgrønland ("East Greenland"), was one of the three counties (amt) of Greenland until 31 December 2008. The county seat was at the main settlement, Tasiilaq. Population in 2005 was around 3,800.
The county was made up of two former municipalities, Ammassalik Municipality and Illoqqortoormiut Municipality, while part of the Northeast Greenland National Park covered the northern half of the county.
It was bordered in the east by the Greenland Sea, Norwegian Sea, Denmark Strait and the North Atlantic Ocean. To the west lies Kitaa.
Coordinates: 70°00′N 31°00′W / 70.000°N 31.000°W