Grimsay, south east of Benbecula is a tidal island of the Outer Hebrides. It is connected to Benbecula by a causeway which carries the B891. In the 2001 census, Grimsay had a population of 19, 20 in 2011 and 27 in 2002.
An extension to the B891 now connects Grimsay to Eilean na Cille to the south east via a causeway. The road was built at a cost of ã1,800 to service the pier at Peter's Port, which was constructed in 1896 at cost of ã2,000 â although the anchorage is awkward and use by people without local knowledge is discouraged.