A hobo jungle is a temporary resting place for hobos. Hobo jungles are generally found in large patches of woods, accessible to railroad lines or yards, and hidden from view. There may be shelter in the form of tarps or tents, and almost always a firepit.

Hobo jungles and similar meeting places allow people who travel the rails to share news of the world, and the area they happen to be in (train schedules, bulls, places to catch out, etc.)

It's probably best to keep your distance from these spots when they're occupied, unless you're invited. Most hobos like to keep to themselves, and have a fierce sense of personal space, due to their transient nature.

there's a little more on hobo jungles under jungle.