Ewloe was sited on high ground within Tegeingl, a cantref in the lands of north-east Wales (Welsh Perfeddwlad).

The lower outer ward is enclosed by two separate sections of wall that meet at a circular fortified tower, which stands upon a rocky knoll.

An external defensive rampart occupies the higher ground to the south of the castle above the neck ditch.

Although a flight of stairs lead up to a first floor gateway—a similarity shared with contemporary military architecture, the shape of the tower does not conform with keeps of the later Plantagenet period.

Llywelyn the Great built a similar D-shaped tower at Castell y Bere at Llanfihangel-y-Pennant in Gwynedd in the 1220s.

If construction commenced in the 1210s, Ewloe may have been a factor in prompting Ranulf de Blondeville, Earl of Chester, to normalise relations with Llywelyn.

After Dafydd ap Llywelyn's defeat, Ewloe appears to have been abandoned by the Welsh when English authority was re-established in this part of north-east Wales.

[3] In 1276, Edward I began the first Welsh War by marching his forces out of the castle at Chester and up the west coast of the Dee Estuary.

Ewloe is not mentioned in the war chronicles of 1276–77 but the presence of what appears to be a siegework outside the castle may suggest it was besieged.

Much of the dressed stone work from its curtain walls and keep had been removed for construction material around Mold and Connah's Quay.

In November 2009, the castle was among five lots of farmland and woodland put up for sale by Flintshire County Council.