Historical records first mention O'Rourke's Baile Nua, or Newtown, in 1541, though the site gained notoriety in 1581 when Brian na Murtha O'Rourke took the drastic step of destroying his own stronghold rather than let it fall into enemy hands. Archaeological excavations conducted by Claire Foley in the 1970s uncovered the foundations of the original tower house, measuring roughly 12 by 9 metres, which once dominated this lakeside fortress.

The tower house stood within an impressive defensive complex that remains largely intact today. The subrectangular bawn wall, roughly 1.4 metres thick and still standing at about 5 metres high in places, retains its original crenellations complete with gun loops; a testament to late medieval military architecture. The eastern side features a two-storey gatehouse with a narrow entrance passage, whilst circular towers guard the northwest and northeast corners, with smaller turrets at the southern angles. The entire complex was further protected by a moat on three sides, measuring 8 metres wide and 2 metres deep, with the southern wall backing directly onto the lake for additional security. Excavations also revealed foundations of various outbuildings against the interior walls, suggesting this was a bustling centre of clan life.

In the early seventeenth century, the site took on new life when Captain Parke constructed a fortified house here, cleverly incorporating the existing medieval bawn and gatehouse into his design. Today, the site is preserved as Parke's Castle National Monument, where visitors can explore both the medieval O'Rourke stronghold and its later incarnation. The castle typically opens to the public from April to October, offering a fascinating glimpse into centuries of Irish history, from Gaelic lordship through English colonisation, all set against the scenic backdrop of Lough Gill.