Amhuinnsuidhe Castle is a large 19th-century private country house on Harris, one of the Western Isles of Scotland.

Originally named Fincastle, the house was built in the Scottish baronial style by architect David Bryce in 1864–1867 for Charles Murray, 7th Earl of Dunmore (styled Viscount Fincastle until 1845), whose grandfather George Murray, 5th Earl of Dunmore had purchased the island in 1834.

[2] The castle is now operated as a venue for fishing, shooting parties, weddings and corporate events.

[3] In 2024 the house was used as a film location for a Gaelic language four-part television drama, An t-Eilean.

It is built of imported freestone, stugged and snecked ashlar; rubbled masonry is used at the rear.