Gustavus Hamilton, 1st Viscount Boyne

Gustavus Hamilton, 1st Viscount Boyne PC (Ire) (1642–1723) was an Irish soldier and politician. In his youth, he fought in his cousin Sir George Hamilton's regiment for the French in the Franco-Dutch War. About 1678 he obtained a commission in the Irish Army. James II appointed him to the Irish Privy Council in 1685.

During the Williamite War Hamilton fought for the Prince of Orange defending Coleraine in 1689, fighting at the Boyne in 1690, fording the Shannon at the Siege of Athlone in June 1691, and fighting at Aughrim in July. George I ennobled him in 1715.