Romerike is a traditional district located north-east of Oslo, in what is today south-eastern Norway. It consists of the Akershus municipalities Fet, Lørenskog, Nittedal, Rælingen, Skedsmo, Sørum and Aurskog-Høland in the southern end (Nedre Romerike), and Ullensaker, Gjerdrum, Nannestad, Nes, Eidsvoll and Hurdal in the northern end (Øvre Romerike).
The Old Norse form of the name was Raumaríki, but the name must be much older (see below). The first element is the genitive plural of raumr m ("person from Romerike"); the final element is ríki n ("kingdom, reich"; cf. Ringerike, Rånrike). In Norse times the lower part of Glomma was called Raumelfr ("the river of the Raums").
Before the unification of Norway, Romerike was a petty kingdom. It had its age of greatness between the 5th and 7th centuries. The 6th-century Goth scholar Jordanes wrote in his Getica about a tribe located in Scandza which he named the Raumarici and which seems to be the same name as Raumariki, the old name for Romerike.