Hi, my name is Pywackt. In game, you may find me playing as JanohWavewalker.
For various reasons, I needed to find out the size of all settlements. This is what I found.
Emerald Hills - 393 squares
Jade Island - 151 squares
Sphene Lake - 401 squares
Phengite River - 312 squares
Agate Shore - 405 squares
Malachite Peninsula - 302 squares
Garnet Bay - 310 squares
This was done by viewing the source of the document and counting all the instances of "onclick="travel_to(".
On a side note. Malachite Peninsula is located very nicely very near the Arkh Quest giver.