Which constellation is named after a mythical river?

Eridanus is the constellation named for a mythical river. It is traditionally drawn as a long, winding stream flowing from near Orion across the southern sky, making it one of the clearest river figures in ancient star maps.

Greek mythology connects Eridanus with the story of Phaethon, the son of the Sun god Helios. After losing control of his father’s chariot, Phaethon was struck down by Zeus. In later traditions, the celestial river represented the route of the runaway chariot or the river where Phaethon’s body fell.

The name Eridanus was also associated with real rivers, especially the Po in Italy and the Nile in Egypt. This blending of mythic and earthly geography explains why ancient writers treated the constellation as a great cosmic waterway rather than a single literal river.

Eridanus was one of Ptolemy’s 48 constellations and remains one of the 88 modern constellations. It is the sixth-largest modern constellation, and its brightest star is Achernar, located at the river’s southern end.