Castle House is situated in the Scottish town of Dunoon, Argyll and Bute.

It sits on top of a promontory called Castle Hill, between West Bay and East Bay, overlooking Dunoon Pier and the Firth of Clyde.

Ewing was a merchant and slave owner and was described by biographer Stephen Mullen as "among the most financially successful of [Glasgow's] élite nineteenth-century sugar/slavery aristocracy".

He used the profits from his business to buy and establish property across London.

[5] The building has been home to Castle House Museum since 1998.