The area has been inhabited since the time of the conquest. At that time, the peninsula, on which today the town stands, was called Digranes.
Borgarnes is considered as the hometown of the poet and Sagahelden Egill Skallagrímsson, which has also set in several sculptural works monuments. The most famous was created by Ásmundur Sveinsson and stands in front of the hamlet Borg á Mýrum, because it is said that Egill lived there. Egil's adventures are recorded in the Egils saga. His father, Skalla-Grímur, was one of the earliest settlers in the area and was the most influential.
The town Borgarnes itself is based on a trade center and a fish processing. So the first houses of the place were built by the Scottish James Richie 1857 in Englendingavík to process salmon. In the area of Borgarnes there are many salmon rivers. The best known are Norðurá (Hvítá) and Grímsá.
From 1929 Borgarnes built a harbor. It became an important hub. They drove to the construction of the bridge by boat to Borgarnes and from there by car.