Bay of Firth is an inlet of the Wide Firth that lies to the North. Within the bay and to the north east of the Holm is the companion islet of Damsay. The causeway from Holm of Grimbister connects to the mainland at Holm Point, just north of the mainland settlement of Grimbister. Haswell-Smith (2004) notes that the islet is farmed.
Although it is clear that in 2007 the island was inhabited, as it was the residence of a candidate for the Scottish Parliamentary Elections in 2007, it was not listed as such by the Census in 2001. Press reports in March 2010 confirmed that at that time the population of the island was at least two. The 2011 census recorded the population as three.
Holm of Grimbister from the east with Finstown beyond