From Halopedia, the Halo wiki
The two Magellanic Clouds are dwarf galaxies that orbit the Milky Way Galaxy. The Large Magellanic Cloud, about 14,000 LY in diameter, is twice the size of the Small Magellanic Cloud whose size is approximately 7,000 light-years. The Large Magellanic Cloud is situated approximately 160,000 light years away, while the Small Magellanic Cloud is around 200,000 light-years away. In comparison to the Milky Way Galaxy, the Magellanic Clouds are metal-poor and gas-rich, with greater fractions of hydrogen and helium.