William Magear Tweed (April 3, 1823 – April 12, 1878), often erroneously referred to as "William Marcy Tweed" (see ), and widely known as "Boss" Tweed, was an American politician most notable for being the "boss" of Tammany Hall, the Democratic Party political machine that played a major role in the politics of 19th-century New York City and State. At the height of his influence, Tweed was the third-largest landowner in New York City, a director of the Erie Railroad, a director of the Tenth National Bank, a director of the New-York Printing Company, the proprietor of the Metropolitan Hotel, a significant stockholder in iron mines and gas companies, a board member of the Harlem Gas Light Company, a board member of the Third Avenue Railway Company, a board member of the Brooklyn Bridge Compa