Jahrain is the name of the region of the world that both Leymos and Karn Bay can be found in. It is not the name of a given country just the geographical region. As such the term is analogous to Iberia or Scandinavia.
Jahrain is northern european in climate, and about twice the size of the united kingdom. It has an extensive coastline but is not an island and connects to a larger mainland (where and what that is currently undecided).
The highlands of Jahrain form a large central plateau in the continent. The small city of Leymos is situated on the edge of the highlands. The highlands are generally wilder and less civilised than the coastal regions – where the larger Jahrainian cities (including Karn Bay) can be found.
For the purpose of this campaign the concept of Jahrain has only been very loosely identified – primarily to have a name for the region and an idea of some of the other points of light that could be reached.