The McDonnells of Knocknacloy are a branch in Ireland

Ireland

Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...

 of the Highland Scottish clan

Scottish clan

Scottish clans , give a sense of identity and shared descent to people in Scotland and to their relations throughout the world, with a formal structure of Clan Chiefs recognised by the court of the Lord Lyon, King of Arms which acts as an authority concerning matters of heraldry and Coat of Arms...

, Clan Donald

Clan Donald

Clan Donald is one of the largest Scottish clans. There are numerous branches to the clan. Several of these have chiefs recognised by the Lord Lyon King of Arms; these are: Clan Macdonald of Sleat, Clan Macdonald of Clanranald, Clan MacDonell of Glengarry, Clan MacDonald of Keppoch, and Clan...

. The McDonnells of Knocknacloy are descended from Somerled Macdonald son of Alastair Og MacDomhnaill

Alexander Óg

Alexander Óg , Lord of Islay , was a Hebridean magnate active at the end of the 13th- and beginning of the 14th centuries...

 and Juliana MacDougall.

They were Gallóglaigh who offered their services to the O'Neills of Tyrone and fought against their cousins the MacDonnell of Antrim and settled at Knocknacloy in County Tyrone

County Tyrone

Historically Tyrone stretched as far north as Lough Foyle, and comprised part of modern day County Londonderry east of the River Foyle. The majority of County Londonderry was carved out of Tyrone between 1610-1620 when that land went to the Guilds of London to set up profit making schemes based on...

.