A mountain range (also mountain barrier, belt, or system) is a geographic area containing numerous geologically related mountains. A mountain system or system of mountain ranges, sometimes is used to combine several geological features that are geographically (regionally) related. On Earth, most significant mountain ranges are the result of plate tectonics, though mountain ranges are formed by a range of processes, are found on many planetary mass objects in the Solar System and are likely a feature of mostterrestrial planets.
Mountain ranges are usually segmented by highlands or mountain passes and valleys. Individual mountains within the same mountain range do not necessarily have the same geologic structure or petrology. They may be a mix of different orogenic expressions and terranes, for example thrust sheets, uplifted blocks, foldmountains, and volcanic landforms resulting in a variety of rock types.