O'Higgins, Ambrosio (ōhĭgˈĭnz, Span. ämbrōˈsyō ōēˈgēns) [key], 1720?–1801, Spanish colonial administrator, b. Ballinary, Co. Sligo, Ireland. Educated at Cádiz, Spain, under the care of his uncle, who was a Jesuit, he went to South America as a trader. After an adventurous career he so distinguished himself in campaigns against the Araucanians that he was appointed (1789) governor of Chile. He was later made marquis of Osorno and served capably as viceroy (1796–1801) of Peru. Bernardo O'Higgins was his son.