A megaparsec is a measurement of distance equal to one million parsecs or 3.26 million light years. Megaparsec is usually abbreviated as Mpc.

The Andromeda Galaxy (M31), which is just visible to the naked eye from a dark observing site, is about 0.89 Mpc away (2.9 million light years), and is one of almost 50 known Local Group galaxies located within 2 Mpc of the Milky Way. Galaxy clusters are typically 1-10 Mpc in diameter, while galaxy superclusters (such as the Virgo Supercluster) are about 100 Mpc across.