The castle, measuring 11.8 metres northwest to southeast and 9.2 metres northeast to southwest, was likely constructed by the Kelly family during the 16th century. Its sturdy construction features well preserved quoins and a defensive base batter, typical of tower houses from this period. The structure sits on a gentle westward slope in the low-lying landscape of Cloghan, also known historically as Cloghankeeny or Carrowncaslane.

By 1623, Myles Cavanagh held a lease on the property, though ownership had passed to Justice James Donnellan by 1641, when he controlled the castle along with 162 acres of surrounding land. The Donnellans were well connected to the powerful Clanrickard Burkes, and James Donnellan himself played a significant role in Irish history as president of the high court that tried many leaders of the 1641 rebellion in 1652. The castle’s defensive features reflect the turbulent times in which it stood; a now destroyed doorway on the southeast wall once led to a lobby with a vaulted guardroom to the north, complete with a light and a double gun loop crafted from dressed stone.

Though much of the interior has been damaged over the centuries, fascinating architectural details remain. The ground floor, accessed through a destroyed doorway that was 1.2 metres wide and 2.2 metres high, features window embrasures on the southwest wall and a gun loop embrasure on the northwest wall. A spiral staircase south of the entrance lobby, though now destroyed, once provided access to at least two upper floors and contained its own defensive lights and gun loops. Perhaps most intriguingly, a quoinstone at the south angle displays a sheela na gig at the second floor level, one of those enigmatic stone carvings found throughout Ireland that continue to puzzle historians and visitors alike.