William R. Roberts (1830 - 1897) was a diplomat, Fenian Society member, and United States Representative from New York (1871 - 1875). Born in County Cork, Ireland, he immigrated to the United States in July 1849, received a limited schooling, and was a merchant in New York City until 1869, until he retired.
In 1865, Roberts was president of the Fenian Society, an Irish nationalist organization noted for its raids on British installations in Canada. He participated in the raid into Canada in 1866, for which he was arrested by the Government.
Roberts was elected to the House of Representatives as a Democrat twice, to the Forty-second and Forty-third Congresses (March 4, 1871-March 3, 1875}. After his time in the House, he was member of the board of aldermen of New York City in 1877, an unsuccessful candidate for sheriff in 1879, and was appointed as Envoy Extraordinary and Minister Plenipotentiary to Chile by President Grover Cleveland on April 2, 1885, serving until August 19, 1889.
He died in New York City in 1897; interment was in Calvary Cemetery, Long Island City, New York.