Though the tower house that once stood here has completely vanished, its strategic position tells us much about medieval defensive architecture in North Tipperary. According to local knowledge, an earthen bank once enclosed the entire site, creating a defensive perimeter around the tower, though this too has been levelled over time.

Today, the only physical remnant of Castle Sheela exists not at its original location, but in the garden of nearby Shannon Hall house. Here, a single door jamb measuring 67 centimetres in length serves as a solitary witness to the castle's former existence. This architectural fragment features a chamfered edge that tapers to a point, a detail typical of medieval Irish tower house construction. Such doorways were designed to be both functional and defensible, with their angled edges making it harder for attackers to force entry.

The complete disappearance of Castle Sheela, save for this lone door jamb, reflects a common fate for many of Ireland's tower houses. Built primarily between the 15th and 17th centuries, these fortified residences were often dismantled for building materials once they fell out of use, their stones repurposed for local construction projects. The site at Shannonhall now exists only as a place name and a memory in the landscape, its commanding position above Lough Derg the sole indication that something significant once stood here.