Messervy O'Keelan (1857-1911) was an Irish-American laborer who lived in Washington DC during the late 19th century. The son of Mason O'Keelan, he followed in his father's footsteps as a factory worker. O'Keelan was a Democrat due to his support for organized labor and opposition to anti-Catholic bigotry. He fathered seven children, including Riley O'Keelan, before dying in 1911.