Termites build various types of nest. Some termites have a completely underground existence, apparently without a central nest. Examples include some species of Amitermes. Others build a central nest in the soil, or in dead or living trees. Many economically-important termites build nests of this type, notably Mastotermes darwiniensis and species ofCoptotermes and Schedorhinotermes. Still other species, for example in the genera Microcerotermes and Nasutitermes, attach their nest to a tree but maintain a soil connection via galleries running down the surface of the trunk. A termite mound is the most familiar form of termite nest.
Mounds are often of very distinctive form, and their size and shape vary from hardened, flat areas to the tall, columnar structures of the spinifex termite Nasutitermes triodiae in northern Australia, which may be more than 7 m high. Typically, each species builds a characteristic mound, although there may be geographical variation in the size and shape of the mound within species. In the mounds ofCoptotermes the outer wall is hard and built of soil and the inner region is generally composed of woody faecal material (carton) and soil.