This 15 km long and narrow county along the northern shoreline of the Reykjanes peninsula derives its name from the many cold springs near the sea. This fresh water runs in great volume underneath the lava fields from the mountains. In the past, people lived there in clusters of small farms or individual ones near the best natural harbours, when open rowboats were used for the fisheries.

The first engine driven boat was introduces in 1907. Gradually the fish stocks diminished close to land because of the increased fisheries by British fishing vessels and people had to seek fish further out. The fisheries in the area peaked in the 19th century, when many fishermen came from different parts of the country to supply their farms for the winter. Individuals started settling permanently, but soon resettled in the villages Hafnarfiord and Reykjavik, when the catch got scarce.

The fishing outfits recovered, when the motorboats became available and soon each farm had one. In 1940, larger vessels, 25-40 tons, were bought and a harbour had to be built for them at Vogar. In 1932, there were 52 small farms in the county, but nowadays most of the people live in Vogar and only a few of the farms are still occupied. The farm Minni-Vatnsleysa is one of the largest pig farms of the country. Sheep have not been bred in the county for a few decades.