Perceptual or vernacular regions are areas that people believe to exist as part of their cultural identity. These regions emerge from people's informal sense of place rather than scientific models.
Formal Region: A region defined by governmental or administrative boundaries (states, countries), physical characteristics (desert, mountain), or economic activities.
Functional Region: A region defined by a system of interactions (usually centered on a node or focal point) like a city and its surrounding suburbs served by common transportation systems.
Cultural Region: An area inhabited by people who have one or more cultural traits in common such as language, religion, or system of livelihood.