

This site is also associated with specific instances of necromantic ritual and/or catabases from the mythic-past. Pausanias describes a river named Acheron in Epirus, Thesprotia, which flows into a swampy-lake and converges with a river Cocytus (like its Homeric counterpart) which Pausanias attributes as the inspiration for Homer's description of the underworld. In some alternative sources Acheron is a lake (rather than/as well as the river) and also functions as a synonym for the underworld.

In some mythological accounts, Charon rows the dead over the Acheron rather than the Styx. It is mentioned in many early sources of archaic poetry but is less prominent and early than the Styx. The Acheron is the river of misery or river of woe.There are several Styx-es in the real world: according to Herodotus, Strabo, and Pliny it was in Arcadia while Pausanias locates one in Nonacris. In later traditions it often serves as the entrance to the underworld over which Charon (the ferryman of the dead) rows the deceased in order for them to enter the underworld. Not only is it an underworld river but is also, more generally, the inviolable waters upon which the gods swear oaths and a goddess in her own right (the daughter of Oceanus and Tethys). It is the only named underworld river mentioned in Homer's Iliad – our earliest mythological text – and three of the Homeric Hymns. The Styx can be considered the most prominent and familiar of the underworld rivers.In the wider mythological tradition, however, there are multiple bodies of water that are associated with the underworld (varying in number and combination depending on the source), the names of which can be understood to reflect specific associations with death.

Guerber assumed that the rivers where Charon sailed mirrored the sky in Greco-Roman thought. Rivers are a fundamental part of the topography of the underworld and are found in the earliest source materials: In Homer's Iliad, the "ghost" of Patroclus makes specific mention of gates and a river (unnamed) in Hades in Homer's Odyssey, the "ghost" of Odysseus's mother, Anticlea, describes there being many "great rivers and appalling streams", and reference is made to at least four specific rivers. The underworld is made solely for the dead and so mortals do not enter it – with only a few heroic exceptions (who undertook a mythical catabasis: Heracles, Theseus, Orpheus, possibly also Odysseus, and in later Roman depictions Aeneas).

The underworld is also considered to be an invisible realm, which is understood both in relation to the permanent state of darkness but also a potential etymological link with Hades as the 'unseen place'. Darkness and a lack of sunlight are common features associated with the underworld and, in this way, provide a direct contrast to both the 'normality' of the land of the living (where the sun shines) and also with the brightness associated with Mount Olympus (the realm of the gods). The underworld itself- commonly referred to as Hades, after its patron god, but also known by various metonyms-is described as being located at the periphery of the earth, either associated with the outer limits of the ocean (i.e., Oceanus, again also a god) or beneath the earth. In early mythology (e.g., Homer's Iliad and Odyssey) the dead were indiscriminately grouped together and led a shadowy post-existence however, in later mythology (e.g., Platonic philosophy) elements of post-mortem judgment began to emerge with good and bad people being separated (both spatially and with regards to treatment). The earliest idea of afterlife in Greek myth is that, at the moment of death, an individual's essence ( psyche) is separated from the corpse and transported to the underworld. In Greek mythology, the Greek underworld, or Hades, is a distinct realm (one of the three realms that make up the cosmos) where an individual goes after death.
