In older times, Ringerike had a larger range which went westward to the municipalities Krødsherad, Modum, and Sigdal, also in Buskerud.

Halvdan Koht suggested in 1921 that the first settlers of Ringerike settled around Tyrifjorden in a ring, though this theory is outdated to many.

[3][8][9] Old Norse: Jórunnr reisti stein þenna eptir 〈au-aun-〉er hana [á]tti, ok fœrði af Hringaríki útan ór Ulfeyj[u].

English translation: Jórunnr raised this stone in memory of who owned her (i.e. was her husband), and (she) brought (it) out of Hringaríki, from Ulfey.

[12] One of the more significant historic people who have lived in Ringerike, was the king Halfdan the Black, father of Harald Fairhair, who united Norway into a single kingdom.

In the early Viking Age before Harald Fairhair became the first king of Norway, Ringerike was a petty kingdom.

Following Harald's consolidation of Norway in the late 9th century, the kingdom appears to have been ruled by a series of local jarls and client kings.

When King Olaf Tryggvason came to Ringerike to spread the novel Roman Catholic religion of the new feudal empire of Charlemagne, Sigurd Syr and his wife allowed themselves to be baptized.