Selfoss is a town in southern Iceland on the banks of Ölfusá river.
It is part, and seat, of the municipality Árborg. The Ring Road (Icelandic: Hringvegur) runs through the town on its way between Hveragerði and Hella. It is a center of commerce and small industries of 6,512 inhabitants (2011), which makes it the largest residential area in South Iceland
