Above is a very crude map of the world as the people of the elder wood know it; a single landmass that is roughly the size of Australia (though not all at the same in terms of climate).
The entirety of this landmass was heavily forested, until the Balachin invasion stripped a massive chunk of it bare; much of it has recovered to some degree, but not all. The current state is this:
Mountainous areas/highlands are shown as grey peaks; deep forest as dark green, lighter forest as a medium green, and grassland (on which there are still plenty of copses and groves) in pale green. The basic flow of the most major rivers (there are plenty of others) is given in light blue, and the ocean in dark blue. The wavy brown lines are "the desolation" - an area devastated by magic, where Balach summoned massive fortress-complexes from Faerie lands (these are now ruined or sealed up).
Overall, the grasslands are most heavily inhabited by the Milia (with Saesin holdouts), and the lighter forest by the Saesin (with a few Milia communities). The deeper forest is almost exclusively Saesin; it is also where the most powerful and ancient covens of witches live. Nobody lives in the desolation, though dangerous faerie creatures sometimes come out from it.