Moynihan is a surname with Irish origin.
Recorded in several spellings forms including Moynihan, Monahan, Monaghan, Monaham, Minihane, Minihan, and probably others, this is an Irish surname of great antiquity. It originates from the Gaelic O' Muimhneachain, which literally translates as "The male descendant of the Munsterman". The surname is most popular in Counties Cork and Kerry, which form part of the province of Munster. The modern spellings are usually Moynihan and Monaghan, the spelling in the 16th century being generally recorded as Minighane, and regarded as the principal surname of West Cork. Michael and Mortimer Moynihan were famous rebels in the late 16th century, and hailed from Skibbereen. Several of the name were famine immigrants into New York, who embarked from Liverpool on the ship "Hampden" bound for that port on December 8, 1846. The first recorded spelling of the family name is shown to be that of Teag O' Muimhneachain, dated 1659, in the Barony of Tulla, during the reign of Richard Cromwell, known as "The Lord Protector", 1658 - 1660. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.