Moycarn (; also Moycarnon, Moycarnanan or Moycarne ) is a barony in County Roscommon, Ireland.
The Irish name Maigh Charnáin means "plain of the cairn." It could also have a connection to Cernunnos, the Celtic hunt god.
Moycarn barony is located in the south of County Roscommon, north of the River Suck and River Shannon; they meet at the southern tip.
The Moycarn barony was anciently called Clan Laithemhain or Muintir Cionaith, ruled by the Gaelic Irish tribes of MacGilla Finnagain (O'Finnegan) and ÃÂ Cionnaoith (Kenny).
It is referred to in the topographical poem Tuilleadh feasa ar ÃÂirinn óigh (Giolla na Naomh àhUidhrÃÂn, d. 1420):
("Mac Gilla Finnegan the mild and the valiant Clan Kenny: two tribes who are fair so be seen rule over the brave Clan Flahavan.")
Notable later families in the barony include the ffrench and Potts.
Below is a list of settlements in Moycarn barony: