Bioregion

A bioregion is a part of the earth's surface whose rough boundaries are determined by natural and human dictates, distinguishable from other areas by attributes of flora, fauna, water, climate, soils and land-forms, and human settlements and cultures those attributes give rise to.

I live in the Cascadia bioregion, a bioregion along the northeast Pacific rim stretching from southeast Alaska to northern California and as far east as the Yellowstone Caldera, defined through the watersheds of the Fraser, Snake, and Columbia rivers.