"In the swamp, we see visions of people we've lost, people we've loved, folks we think are gone. But the swamp tells us they're not. We're still connected to them. Time is an illusion and so is death."
— Huu explaining Team Avatar's illusions.
The Foggy Swamp, often referred to as The Swamp, is a vast, mysterious wetland covering a large portion of the southwestern Earth Kingdom. The swamp is densely populated by a variety of fauna and flora, the most notable being the catgator.
The local population consists of a tribe of waterbenders, who migrated to the swamp from the South Pole centuries prior to the outbreak of the Hundred Year War. The tribe maintains a strong relationship with nature; they navigate the dense undergrowth with skiffs, where they forage for sustenance.
At the center of the swamp stands an enormous, ancient banyan-grove tree whose roots spread out over miles. The rest of the swamp grew by extending from the foundations of this tree, over time developing into one large, living, super organism. The Foggy Swamp Tribe bases its philosophy on this phenomenon; they believe that, like the tree, all people of the world, no matter how different, retain the same roots and are branches of the same tree. Toph Beifong used her seismic sense and this connection of the swamp, the roots and vines that run everywhere, to see what goes on in the world.
The swamp possesses deep spiritual qualities as well; enigmatic weather patterns and induced visions of the past, present, and future are commonplace within the swamp. One particular waterbender named Huu was able to reach enlightenment under the banyan-grove tree at the very heart of the swamp and, using his abilities, fiercely protected the swamp from any who wished to harm the place by becoming a giant swamp monster made up of vines controlled through the manipulation of plants.