Earnán Mac Coilín (died 25 September 1642) was an Irish Confederate irregular who served under Seamus Hennessey during the Irish Confederate Wars. Enlisting in Hennessey's irregular company to escape rural poverty, he first fought at the Battle of Ballinaculla on 13 September 1642, and he took part in several clashes with the Parliamentarians until Hennessey's army was wiped out, and all but Hennessey killed, at the Battle of Rossadrehid later that month.