The conventional date given for the settlement of Iceland is 874, plus or minus a couple of years. In terms of evidence of human activity before settlement, yes there may be. But don’t let your imagination run away from you: there are several caveats.
To speak first of historical evidence, there are references in medieval Icelandic literature to people called the “Papar,” an Icelandic name likely referring to the pope. This name refers to a group of Irish monks who supposedly settled parts of Iceland, including the island of “Papey.” There is no archaeological evidence of their dwellings, only some historical and literary references in the medieval material. In Landnámabók (The Book of Settlements), these mysterious monks were said to have left behind relics like books and croziers, departing the country upon the arrival of the Norse settlers. While there are many examples of Irish monks from the early medieval period looking for isolation in remote environments, some scholars have more recently interpreted the Papar as a literary trope, by which medieval Christian Icelanders tried to re-write Christianity into their pagan past.
There is however some limited evidence for human activity in Iceland before the traditional date of settlement.
Around 871 (again, plus or minus a couple of years), a volcanic eruption spread a layer of tephra across much of the island, which archaeologists now refer to as the settlement layer. Any archaeological evidence for activity in Iceland before settlement would necessarily need to be found under this layer.
Recent excavations in Stöðvarfjörður in East Iceland have been found underneath the settlement layer, for instance. The excavations, led by archaeologist Bjarni Einarsson, have unearthed one of the oldest and largest longhouses in all of Iceland, in addition to a rich hoard of jewellery and coins. Radio carbon dating places these structures decades prior to the traditional settlement date, though it is worth noting that radio carbon dating always has a margin of error. Still, its presence beneath the settlement layer seems to definitively place it some time prior to 874.
Bjarni has advanced the theory that prior to settlement, Iceland was dotted by seasonal hunting camps, where Norwegians might have set up summer bases for hunting whale and walrus. Such seasonal hunting camps were common in other lands known to Scandinavian seafarers, such as in Greenland and L’Anse aux Meadows, the short-lived Viking settlement in the New World. It may have been the case that prior to the migration of Norse settlers in the 9th and 10th centuries, seafarers may have known of Iceland and even spent time there prior to their migration.
To summarize: there is definitely evidence, but maybe not proof, of human activity in Iceland prior to settlement. While impossible to prove (at the moment), it is a fun possibility to think about!
