 Donogh O'Brien, 4th Earl of Thomond

Donogh O'Brien, 4th Earl of Thomond and Baron of Ibrickan (; died 5 September 1624) was an Irish nobleman and soldier noted for his loyalty to the Kingdom of Ireland.His long-term objective, achieved after decades, was to obtain an official acknowledgment that County Clare, where his possessions were situated, was part of the province of Munster, to free it from the jurisdiction of the Connaught government under which it had been placed.