Solstheim is a location in Skyrim: Dragonborn
It is the main setting where the Dragonborn DLC takes place
It is located northeast of Windhelm
How to get to There
Solstheim is an island north east of Windhelm. Has a small dark elf town called Raven Rock and a handful of Nords living in Skaal Village. People don't usually sail over there unless they have a particular reason. It can be a pretty rough place.
Solstheim was part of Skyrim until the High King gave it to Morrowind in 4E 16 to serve as a refuge for the Dunmer after the events of the Red Year.