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You will be placed on Little Butte at the beginning of the game. Your first quest is to find a den to raise your pups at. There are three dens to choose from. A fourth den can be unlocked with 25,000 experience points; however, it is not recommended due to glitches. Upon entering the den site of choice, it is suggested that you keep heading in the same direction. More often than not, you'll find the den. A Wikia Contributor
East Creek territory
East Creek is the "fourth" den territory, located south of the creek and slightly north of the Bison Peak Cutoff territory. It can be unlocked once the player has achieved at least 25,000 experience points during Amethyst Mountain or before selecting a den in Slough Creek. (Unverified) Upon unlocking, you will find four den sites highlighted on the map instead of the usual three. There are some notes regarding this fourth territory that should be noted before choosing the den and progressing, however.
While unintentional, the territory is regarded as the glitchiest site. Puppies have a tendency to wander/roam far from the area. It's not possible to keep them anchored in this territory due to this behaviour. Predators seem to be more common in this one territory alone. It's usually advisable to steer clear of this territory at all costs, though if you're up for a challenge, it's a good "hard-mode". ~Neam 06:55, October 14, 2013 (UTC)