Harlech occupies a strategically defensible site, looking out towards the sea; the battlements rise from an almost vertical cliff face, while any landward attackers would first have to deal with a massive twin-towered gatehouse. It is believed that the castle was originally actually on the sea, for ease of re-supply, but that the sea has now receded.
The fortress's massive inner walls and towers still stand almost to their full height. The views from its walls are panoramic, and stretch from the seascape in front to the mountains of Snowdonia behind.
Master James of St. George, familiar as the military architect of most of Edward’s castles, managed to blend .the natural elements of the site to the defensive requirements of a fortress. The result is a building of rare beauty and grace

Edward the first’s army arrived at Harlech in 1283, and almost straight away work started on the castle It was a key castle in Edward's ring of castles in North Wales. A major army of workmen constructed the castle over the next six years.
The final result was a perfectly concentric castle, where one line of defence, is enclosed by another. The natural strength of the castle rock on the landward side and cliff face on the seaward side meant that only the east face was vulnerable to attack. It is therefore on the east side that a massive gatehouse was constructed with a series of heavy doors, narrow passages and three portcullises. Master James himself, was the Governor of the castle from 1290 to 1293

The castle could be supplied by sea, so on the seaward side there is a gated and fortified stairway plunging almost 200 ft down to the foot of the castle rock. Supplies could be raised to the castle up this stairway. In fact during a siege in Madog ap Llywelyn's uprising of 1294-95, ships from Ireland supplied the garrison.

Ironically, in 1404 Welsh leader Owain Glyndwr took the Castle. He made it his home and headquarters he also proceeded to hold a parliament here. And it was only after a further, long siege in 1408 that English forces under Harry of Monmouth, later Henry V, retook Harlech.
The castle was held for the Lancastrians until taken by Lord Herbert of Raglan for the Yorkists.

There is lots of history associated with the castle - Owain Glyndwr’s wife was taken prisoner here by Henry V, and of course there is the song, 'Men of Harlech', written to commemorate the bravery of the defence of the castle during the Wars of the Roses. It was the last castle in the country to be held by the Royalists during the Civil War. Contrast Caernarfon held by the Cromwellians - not all of Snowdonia, let alone Wales was on the same side
Today it is very peaceful, and there are spectacular views out to sea and to the Lleyn Peninsula