Ignatius Loyola Donnelly (1831 –1901) was a U.S. Congressman and a prominent Minnesota leader of the Populist Party from 1890-1896. He was a Radical Republican Congressman from 1863–1869 and a Minnesota state legislator. He advocated extending the powers of the Freedmen's Bureau and was an early supporter of women's suffrage. He outlined the Populist credo in 1877. After leaving the Minnesota State Senate in 1878, he returned to his law practice and writing. Donnelly was also an amateur scientist, known primarily now for his theories and books concerning Atlantis and other pseudo-disasters. Donnelly's work had important influence on the writings of late 19th and early 20th century figures such as Helena Blavatsky, Rudolf Steiner, and James Churchward.