Geologists consider the four major landforms to be hills, mountains, plains and plateaus. Other minor categories of landforms include, but are not limited to, canyons, valleys, buttes, basins, bays and peninsulas.
In geology, a landform is any naturally occurring formation of dirt and rock regardless of its size. Man-made formations, such as canals and ports, are not considered landforms. Geologists typically classify a landform by its physical characteristics, the most important of which are the arrangement and structure of its materials, the steepness of its slope, the speed at which it drains water and the process by which it was formed.