Formal, functional and perceptual regions comprise the three classifications of regions that are used to organize complex spaces into simpler divisions. These regions are the areas of interest in the fields of geography, cartography and engineering.
In geography, a region is a portion of the earth's surface that is characterized by a level of similarity based on certain features. A formal region, also referred to as "homogeneous region," is an area where people share commonalities determined by facts, such as language and climate. A functional region is identifiable through its central point, which serves as a hub for the region's communication, transportation or economic processes. A perceptual region, also called a "vernacular region," is associated with a group's subjective notion of a place, such as the Midwest or the Sun Belt.