Old Keiss Castle is located just outside the village of Keiss along the coast of Caithness. To access the castle, head down towards Keiss Harbour, and then follow the footpath along the coast towards the castle. Access to the start of the footpath is just past 4 holiday pods.

Old Keiss Castle was built in the late 16th century by George Sinclair, Fifth Earl of Caithness. It stands at the northern end of Sinclair Bay and was one of three fortifications that controlled this territory (the others were Ackergill Castle and Girnigoe Castle).

The first record of the castle dates from 1623 when George defied King James VI (I of England). In response, the King dispatched Sir Robert Gordon to raid Caithness and, although the rebellious Earl provisioned his castles for a siege, he withdrew to Orkney. All three castles surrendered without a fight to Sir Robert but were eventually returned to the Earl’s son - George, Lord Berriedale.

In 1643 the castle passed to George Sinclair, Sixth Earl of Caithness. He built Thurso Castle which he used as his main residence with Keiss being allowed to decay. This was only exacerbated when the Sinclairs found themselves embroiled in a bitter dispute over land and title with the Campbells of Glenorchy. First the courts, then the King supported the latter, prompting Sinclair to mount a protracted guerrilla campaign against his rivals.

It was only intervention by James, Duke of York (later King James VII and II) that the Sinclairs were restored. By this time, Keiss Castle itself was ruinous although some repairs were made over the following decades for some form of dwelling.