Cairn was the name of a small croft high on the hillside above Wasbister and was situated between those of Ploverhall and Shalter.
In 1871 Cairn was occupied by 38-year-old fisherman James Inkster and his wife Ann. The extent of the land covered 9.5 acres, for which James paid an annual rent of £1.
In 1888 Magnus Alexander lived at Cairn as a sub-tenant of Feolquoy. Sub-tenants were declared not to be crofters, so his rent stayed at £2.10.0.