Okay, so I went and did some research mostly on the Nilfgaardian provinces, and what I got is mostly a headache and a lot of confusion.
After that, I thought of unifying the counties on that awesome map, and this is what came out.
So while the Northern Kingdoms are known and defined, I still have a lot of doubts about the correct location of whatever lies below the Yaruga. Based on what the Wiki says, the indication we have are the following.
- Just below the Yaruga, from west to east there are Cintra, Upper Sodden, Angren and then the Blue Mountains. So far so good.
- South of Cintra lies Nazair: the sea to the west, Cintra and Upper Sodden to the north, Mag Turga to the east and the river Yelena to the south, beyond which lies Mettina.
- Mag Turga is between the Amell Mountains and Tir Tochair (another mountain range), then there's probably Toussaint, which lies in some mountains. Seems to be placed south of Angren and east of Mag Turga.
- Mettina is bordered by the Yelena to the north, the Sylte river to the south and the sea to the west. East of Mettina is Geso, and south there are Ebbing and Maecht.
- Geso is west of Tir Tochair and is separated from Maecht by the Velda river to the south. I'd place it below Toussaint and almost at the same height of Mettina.
- Maecht is described as bordering with Mettina (north), Geso (north and east) and Ebbing (south).
- Ebbing is a large province which goes from the sea to the west to Maecht and the Korath desert to the east.
- Of Gemmera we only know that it's in the south; Etolia is "on the southern coast", Vicovaro is "one of the southernmost provinces", and Ymlac and Rowan are close to each other, but the latter is quite far from the capital.
All this considered, I tried to place them as best as I could without touching the borders, but there's still some conflict with the plethora of custom and official maps. Opinions?