Regions are a means for geographers to classify, categorize, or simplify Earth's surface. A primary concern of geography is how and why one part of the Earth is different from other parts. Given the vast size and variety of environments, both natural and human, on Earth's surface, it is practical for geographers to divide the Earth into more manageable pieces. Regions are tools that allow geographers to focus their inquiries onto manageable areas. The division into manageable pieces extends from global to very local scales, since regions may be as large as continents and as small as neighborhood blocks.

Regions are based on a commonality, sameness, similarity, or homogeneity. The homogeneity may be based on characteristics of the physical environment (climate, vegetation, or landforms), on human ...