Borders of Foo

There are four borders surrounding the country of Foo. They are the Guarded Border (North), Hard Border (East), Wet Border (South), and Hidden Border (West). There is a fifth, secret border that very few in Foo know about. It is known as the Sky Border.

History
It was mentioned by Geth that long before the arrival of Leven or even Sabine, the land of Foo stopped expanding. It appeared to have reached its maximum territorial expansion. However, Geth strongly believed that one day, when dreaming reaches a new level, the borders would be lifted and Foo allowed to grow larger again. The only border that actually appears in the novels is the Hard Border. It is described as an impossibly long wall traveling as far as the eye can see in both directions, and reaching up far into the sky. The Hidden Border is an enormous bank of fog stretching off endlessly through the mountains above the Invisible Village and out over the Veil Sea.

Although the other borders physical appearences are unknown, theories have been formulated on what they might look like

Wet Border: A great chasm spanning the Veil Sea west of Sycophant Run in which water poors endlessly into an abyss.

Guarded Border: A wall, differing from the Hard Border in the fact that it appears to be man-made.

Sky Border: Although the Sky Border never appears in the novels, it is described to the whisp form of Janet Frore the talking boulder. The stone had fallen from the very top of the Hard Border and landed upon the head of an unfortunate soul who happened to be standing in the wrong place at the wrong time. This incident bestowed upon the stone the temporary abilty to speak. The stone tells Janet that it once could see all of Foo from the top of the Hard Border (making no mention of the other side however), but reveals that it, like the other boulders in the wall always strived for something more. They wanted to reach farther up into the sky. The one thing that prevented them is the Sky Border. The vast majority of the time, the sky above Foo is clear, as the inhabitants can see the large celestial objects, such as the many suns and moons; but should any nit or stone be foolish enough to venture too far up, the Shale take action and deny them access. The Shale are birds that usually fly far and wide across Foo in small groups, and are almost never seen by the people on the ground, but when something attempts to cross the Sky Border, they can fly together and create a tight, impenetrable barrier in front of the offender.

"Most of Foo don't even know they exist."

The Talking Boulder on the Shale of the Sky Border

Beyond the Borders
In the first set of novels, it is never revealed what is beyond the borders of Foo, but in Geth and the Return of the Lithens, Geth and Clover are ripped from the land of Foo and dragged through the Hard Border and into the land of Zendor. It is unknown how large Zendor is, whether it is just concentrated behind the Hard Border or whether it completely encircles the land of Foo. It is also unknown if Zendor has its own borders.