An island lying in the channel between North Uist and Benbecula, Grimsay (Gael: Griomasaigh) is the largest of the low-lying stepping-stones which convey the North Ford causeway carrying the A865 Trunk Road between these islands. This causeway lands on the northwest tip of Grimsay.
Grimsay is about 3 miles (5 km) in length and 1½ miles (2.5 km) wide and includes a number of small lochans. Its population has been unstable; having declined from 239 (1961) to 193 (1971), it rose to 204 (1981) and 215 (1991), but then fell again to 201 (2001) and 169 (2011). The island has a harbour at Kallin, which is the base to a sizeable shell-fish industry. Kallin is also home to The Boatshed, a marine repair facility which promotes traditional skills and includes a museum. There is a fine example of an Iron-Age wheel-house on the northeast coast of the island.