According to descriptions in Landnámabók and several sagas, written long after settlement of Iceland, some of the first settlers brought high-seat pillars with them from Norway. Once land was sighted, the high-seat pillars were thrown overboard, and a permanent farm was established where the pillars washed ashore. The first farm established in Iceland, located where the capital, Reykjavík, stands today, was allegedly founded using this method.
Source: Öndvegissúlur – Wikipedia
Tim B.
https://en.wikipedia.org/wiki/Reginnaglar