The Small Kingdoms is a region within the Four Corners of Civilization.
The Small Kingdoms border the Aturan Empire, Modeg, Vintas, and the Centhe Sea, with a smaller section next to the Stormwal Mountains, and another south of Vintas. It has only one island, which contains the city of Junpui. In Junpui they have harsh punishments for law-breaking, including decrepication - or throwing someone into a fire - for forging documents.  “Only priests and fools” expect the roads in the Small Kingdoms to be safe. 
It's unspecified whether the Small Kingdoms itself is a nation, or simply a collection of sovereign states that are referred to cohesively for the sake of simplicity. According to Arwyl, people in the Small Kingdoms drink Bredon beer when they're pregnant, brewed with flower pollen, fish oil, and cherry stones. It likely that Yll is considered to belong with this conglomeration. 
In the Chronicles
Vashet spent four years as a captain and bodyguard to a "poet king" in the Small Kingdoms.