In geography, regions are areas that are broadly divided by physical characteristics (physical geography), human impact characteristics (human geography), and the interaction of humanity and the environment (environmental geography). Geographic regions and sub-regions are mostly described by their imprecisely defined, and sometimes transitory boundaries, except in human geography, where jurisdiction areas such as national borders are defined in law.
Apart from the global continental regions, there are also hydrospheric and atmospheric regions that cover the oceans, and discrete climates above the land and water masses of the planet. The land and water global regions are divided into subregions geographically bounded by large geological features that influence large-scale ecologies, such as plains and features.
Global regions distinguishable from space, and are therefore clearly distinguished by the two basic terrestrial environments, land and water. However, they have been generally recognised as such much earlier by terrestrial cartography because of their impact on human geography. They are divided into largest of land regions, known as continents, and the largest of water regions known as oceans. There are also significant regions that do not belong to either classification, such as archipelago regions that are littoral regions, or earthquake regions that are defined in geology.
Regional geography is a branch of geography that studies regions of all sizes across the Earth. It has a prevailing descriptive character. The main aim is to understand or define the uniqueness or character of a particular region, which consists of natural as well as human elements. Attention is paid also to regionalization, which covers the proper techniques of space delimitation into regions.
Regional geography is also considered as a certain approach to study in geographical sciences (similar to quantitative or critical geographies; for more information, see history of geography).