This is a list of named geological features on Io, a moon of Jupiter. See also the list of mountains on Io and the list of paterae on Io.

Eruptive centers on Io, locations typically where major volcanic activity was observed and characterized before the volcanic landform was, are named after the gods of volcanoes and/or blacksmiths in various mythologies.

On Io, catenae /kəˈtiːnə/ (crater chains, sg. catena) are named after sun gods in various mythologies. In 2006, the use of the term catena was discontinued in favor of the patera /ˈpætərə/ (plural paterae /ˈpætəriː/). Below is a list of features that previously used the descriptor term catena.

Ionian fluctus /ˈflʌktəs/ (areas of lava flow)^[1] are named after fire and thunder gods in various mythologies, or after locations in Greek mythology associated with Io.

Ionian mensae /ˈmɛnsiː/ (mesas, sg. mensa) are named after mythological figures associated with fire or with the nymph Io.

Ionian montes /ˈmɒntiːz/ (mountains and volcanos, sg. mons /ˈmɒnz/) are named after people and places associated with the nymph Io, and sun and fire gods in various other mythologies.

Ionian paterae /ˈpætəriː/ (shallow craters and crater chains) are named after sun gods and fire gods in various mythologies.

Ionian plana /ˈpleɪnə/ (plateaus, sg. planum /ˈpleɪnəm/) are named after locations in Greek mythology associated with the nymph Io.

Ionian regiones /rɛdʒiˈoʊniːz/ (regions, sg. regio /ˈriːdʒioʊ/) are mostly named after locations in Greek mythology associated with the nymph Io.

Ionian tholi /ˈθoʊlaɪ/ (hills, sg. tholus /ˈθoʊləs/) are named after mythological figures associated with fire or with the nymph Io.

• USGS: Io nomenclature