The
Kuiper belt [See Link] is a region of the Solar System beyond the planets extending from the orbit of Neptune at around 30 AU to approximately 55 AU from the Sun.
It is home to at least three dwarf planets -- Pluto, Haumea and Makemake. While the asteroid belt is composed primarily of rock and metal, the Kuiper belt objects are composed largely of frozen volatiles ("ices"), such as methane, ammonia and water.
1 AU = ~ 150,000,000 kilometers or 93 Million miles
25 AU = ~ 3,750,000,000 kilometers or 2,325,000,000 miles