Örfirisey is a former island close to Grandi and the old harbour area. Previously the island held a monastery, a merchant trade company and possibly ship building. Accounts exist of grain being bought and sold on the island. In the late 19 century a storm destroyed many of the buildings on the island but more soon reappeared and the island was bought by the city of Reykjavik. A spine of rock leading to the island was made larger in order to give full-time access to the island where prevously it was only possible during low tide. During WW2 British troops used the area as a harbour for bringing supplies and built buildings for storage. In 1950 a larger oil depot was built where it still stands today and in 1980 more land was filled out to create a larger industrial area.
One can walk from Grandi to the area along a coastal pathway, this geocache is located a little out of the way of the main path, but is one of my favorite spots in the area to come to with the dog for some morning peace.
Reference: http://icelandictimes.com/grandi/ (for more info on Grandi)
