Ranrike (Old Norse Ránríki) was the old name for a part of Viken, corresponding to southeast Norway (Oslofjord area) and the northern half of the modern Swedish (Norwegian until 1658) province of Bohuslän (roughly identical with Álfheimr of Scandinavian mythology).
Jordanes does give us a terminus ante quem for the use of Ragnaricii/Ranii: One king, Rodwulf of the Ranii (identified by some with Ranrike), had left his kingdom to join Theodoric the Great in Ravenna.
In any case, the position of Ragnaricii next to Raumaricii (Romerike) indicates that it is probably the same as Ranrike, believed to be named after the goddess of the sea, Rán (Ran-riki, "reich of Ran or, as sometimes translitterated in 19th century sources, Rån").
Another parallel supports this derivation: Pliny the Elder's Saevo mountain range, probably meaning "sea land", refers in part to Ranrike (see under Scandinavia).
The latter word is easily open to translation, coming from two segments, riki "kingdom" and ragna "of the rulers", meaning the gods (see under Ragnarök).