Short-period comets that originate beyond the orbit of Neptune but are generally moving level with the orbits of other planets are in the Kuiper Belt.

The Kuiper Belt is a disk-shaped region of icy bodies that extends from Neptune's orbit outward to about 50 AU (astronomical units) from the Sun. Short-period comets, which take less than 200 years to complete an orbit around the Sun, are thought to originate in the Kuiper Belt and get gravitationally disturbed into the inner solar system.