Hirta is the largest island in the St Kilda archipelago, on the western edge of Scotland. The names Hiort and Hirta have also been applied to the entire archipelago. Now without a permanent resident population, the island had nearly all of St Kilda's population of about 180 residents in the late 17th century and 112 in 1851. It was abandoned in 1930 when the last 36 remaining inhabitants were evacuated to Lochaline on the mainland.

St Kilda is a remote archipelago situated 64 kilometres (40 mi) west-northwest of North Uist in the North Atlantic Ocean. It contains the westernmost islands of the Outer Hebrides of Scotland. The largest island is Hirta, whose sea cliffs are the highest in the United Kingdom; three other islands were also used for grazing and seabird hunting. The islands are administratively a part of the Comhairle nan Eilean Siar local authority area.