The massive complex of Girnigoe Castle has an importance second to none in the medieval history of the north of Scotland and is the most spectacular ruin in this part of Britain.
Located about three miles north of Wick it is dramatically and grandly situated on a long narrow rock, with perpendicular faces, projecting into Sinclairs Bay and the North Sea. The rocky peninsula rising fifty to sixty feet above the sea runs diagonally to the mainland, and is separated from it by an arm of the sea known as a goe or voe. This is a Norwegian word and means a cave, a rocky inlet or creek or a deep ravine that admits the sea. On this was built, between 1476 and 1496, the impregnable castle on what appears to be the site of an earlier Viking fortification.
The construction was of local stone, of which some would have been quarried when building the ditches, with the exception of the red sandstone lintels and corner stones that probably came from Freswick to the north. The main part of the building, which constitutes the best of the ruins, was a keep three or four stories protected from a mainland attack by two great ditches, one of twenty feet and the other of fourteen feet cut into the peninsular. Built on the plan of a parallelogram, thirty-six feet by twenty-six feet over the walls having two wings on the eastward or seaward side of the rock.
The main entrance is an arched passage on the West Side, which was designed so that a man could enter on horseback without dismounting. It was accessed from the gatehouse situated between the two ditches and over which Sinclair Castle was later built by a drawbridge. The corbels for supporting the bridge still exist.
Below ground level there was a well room where a spring, long covered over provided fresh water. Also underground is a dungeon and these rooms are vaulted in contrary directions, and the whole of the ground floor is also vaulted. The hall measuring thirty feet long by nineteen feet wide and thirteen feet high occupies the whole of the first floor. It was lighted on all sides except the north across which was a bretasche.
The window over the main entrance was a lovely oriel window supported on corbelling, with mullions and transoms, and a sloping stone roof, at the apex of which there was a carved stone with the crest of the Earls of Caithness.
Adjoining in the north wing is another room, in which there is an access door in the floor to an arched room about seven feet high set above the former kitchen vaults. Its existence is impossible to detect from outside and thus provides a strong room with great security.
To the seaward side of the keep were a number of outbuildings being either one or two stories high with either a passage or a courtyard between them. At the extreme end of the promontory and some fifteen feet below the general level was another building measuring about thirty-five feet by nineteen feet. In it there is a stepped access way cut out of the rock down to the sea on the north side.
As was often the case in these times the accommodation offered by the keep was insufficient for the new requirements so in about 1606 a further castle, known as Sinclair Castle, was built on the land to the west of the keep and between the two ditches. Once again access was provided across a drawbridge from the mainland and the castle was architecturally more sophisticated than Girnigoe with finely carved corbels for supporting angle windows and turrets. Girnigoe was built for strength and Sinclair for beauty. It is in a greater state of ruin than Girnigoe as it received most of the punishing cannon fire when the castles were attacked in about 1690.