The
Kingdom of West Breifne (Irish
Breifne Ua Ruairc) was an historic kingdom of Ireland that existed from 1256 to 1605, located in the area that is now
County Leitrim. It took its present boundaries in 1583 when West Breifne was shired and renamed Leitrim, after the village of
Leitrim, which was an O'Rourke stronghold. The kingdom came into existence after a battle between the O'Rourke clans and the O'Reillys caused the breakup of the older
Kingdom of Breifne and led to the formation of
East Breifne and West Breifne. The Kingdom was ruled by the various O'Rourke clans and lasted until the early 17th century, when the
Kingdom of England confiscated their lands.