Which constellation contains the Andromeda Galaxy?

The Andromeda Galaxy is contained in the constellation Andromeda.

Andromeda is a northern constellation named for Andromeda, the princess in Greek mythology who was chained to a rock and rescued by Perseus. Its most famous deep-sky object is the Andromeda Galaxy, also called Messier 31, M31, or NGC 224. The galaxy appears as a faint, extended patch within Andromeda’s boundaries.

The Andromeda Galaxy is a barred spiral galaxy and the nearest major galaxy to the Milky Way. Under dark skies, it can be seen without a telescope, although binoculars and telescopes reveal more of its structure and its companion galaxies, Messier 32 and Messier 110.

The answer is sometimes confused with Pegasus because Pegasus helps form the recognizable Great Square near Andromeda. Cassiopeia is also a useful guide for locating M31, but the galaxy itself lies in Andromeda. Triangulum contains another nearby galaxy, M33, not the Andromeda Galaxy.