In geography, a plain refers to a flat area with little or no changes in elevation. It is one of the world’s major landforms.
Plain is also defined as any relatively level area of the Earth’s surface exhibiting gentle slopes and small local relief. Plains vary widely in size. The smallest occupy only a few hectares, whereas the largest cover hundreds of thousands of square kilometres—as, for example, the Great Plains of North America and the expanse of gently undulating land that sweeps from the Pyrenees Range on the French–Spanish border across northern Europe and Asia almost halfway around the world nearly to the Bering Sea.
Occupying slightly more than one-third of the terrestrial surface, plains are found on all continents except Antarctica. They occur north of the Arctic circle, in the tropics, and in the middle latitudes. Corresponding to their broad geographical distribution, the plains of the world show considerable variation in vegetation. Some are tree covered and others are grassy. Still others support scrub brush and bunch grass, while a few, which are nearly waterless deserts, have only the most sparse and scanty plant life.
Plains are usually found at the foot of mountains, by the coasts, at valley bottoms, or on the upper surface of plateaus. Plains are often the most densely inhabited places in the world. The relative ease of transport along level land favors human settlement. Plains in many parts of the world are important for agriculture. Interestingly, plains also occur underwater where they constitute part of the seafloor. Such plains are called abyssal plains.