The castle consists of an almost square tower, measuring 11.2 metres in length and 10.6 metres in width, which rises three storeys despite significant deterioration over the centuries. The northwest corner has completely collapsed, and several breaches puncture the remaining walls, offering glimpses into the building’s medieval construction.

While time has not been kind to Fartamore, several architectural features still hint at its former grandeur. The springing of an arch visible at the top of the eastern wall indicates that a stone vault once covered the interior, a common defensive feature in Irish tower houses. Through a breach in the same wall, visitors can spot the exit chute of a first floor garderobe; essentially the medieval equivalent of an en suite bathroom. A broken embrasure in the north wall reveals a built in wall cupboard, one of the few domestic conveniences that survive from the castle’s heyday.

The castle wasn’t merely a standalone tower but part of a larger fortified complex. About four metres west of the southwest corner, remnants of a bawn wall extend westward for five metres before turning north for approximately 23 metres. Though no surface traces remain of the northern, eastern, or southern walls, the surviving section suggests the tower once stood within a protective enclosure typical of Irish castles from this period. Earthworks to the west and northwest of the castle provide further evidence of the site’s former extent and importance in the local landscape.