A region of the Solar System that extends outwards from the orbit of Neptune (30 AU) to about 50 AU, equivalent to between 4.5 and 7.5 billion km from the Sun. It's predominantly composed of small icy rocky bodies. Three dwarf planets inhabit the Kuiper belt, Pluto, Quaoar and Eris.
The Kuiper Belt is thought to be the source of short period comets with ecliptically inclined orbits.