Selfoss is a town in southern Iceland on the banks of the Ölfusá river.
It is a part of, and the seat, of the municipality of Árborg. The Icelandic Ring Road (Icelandic: Hringvegur) runs through the town on its way between Hveragerði and Hella. The town is a centre of commerce and small industries with a population of 6,934 (2016), making it the largest residential area in South Iceland.
The town is located about 11 km inland from the southwestern coast of Iceland, and 50 km from Reykjavík. It is the major town and the administrative seat of the Southern Region. The closest other towns are Eyrarbakki, Stokkseyri and Hveragerði.
Source: https://en.wikipedia.org/wiki/Selfoss_(town)