A small islet surrounded by rocky slopes on the northeast coast of Lewis in the Outer Hebrides, Dun Eistean (sometimes Dun Eistein or Dun Uisdean) was the ancient stronghold of the Morrisons of Ness. Lying a quarter-mile (0.5 km) northeast of Knockaird and first occupied in mediaeval or perhaps even prehistoric times, it was here the Morrisons made their last stand against the MacLeods in the 16th century.
Although little remains of the fort, this Scheduled Ancient Monument was subject to archaeological investigations by the University of Glasgow between 2000 and 2004, and a bridge to the island was opened in 2002 to improve access.
The island is now owned by the Clan Morrison Society.