Castlederg (earlier Caslanadergy, from Irish: Caisleán na Deirge, meaning “castle upon the Derg”) is a village in County Tyrone, Northern Ireland. It lies upon the River Derg and is near the connect with County Donegal. It stands in the townlands of Castlesessagh and Churchtown, in the historic barony of Omagh West and the civil parish of Urney. The village has a ruined castle and two ancient tombs known as the Druid’s Altar and Todd’s Den. It had an population of 2,985 people in 2011.
The village hosts some of the district’s key events each year, including the Derg Vintage Rally, Dergfest music festival, Red River Festival and the conventional Apple Fair which sees the apple growers of County Armagh visit to sell their wares.
Traditionally, Castlederg was a traveller’s stop along the ancient pilgrimage route to Station Island upon Lough Derg. The town boasts ancient ruins and monastic settlements.