'Green Wilderness') is a forest in Poland which extends from the Narew River and the border with the region of Masuria.

The forest lies in a lowland and contains a wet sandy soil, but it is rich in various minerals which are mined.

The forest was first ordered colonized by Duke Janusz I of Warsaw in the first half of the 14th century by peasants and petty nobles.

Colonization continued on and off subsequently, and its inhabitants, because of their isolation by living deep in a forest, developed a distinct culture.

Other neighboring Poles gave them the name of kurpś, because they retained their ancient tradition of making shoes made of fibers from the linden tree and sealed with lime.