William Marcy Tweed (April 3, 1823 – April 12, 1878), known as "Boss Tweed," was an American politician most famous for his leadership of Tammany Hall, the Democratic Party political machine that played a major role in the politics of 19th century New York. At the height of his influence, Tweed was the third-largest landowner in New York City, a director of the Erie Railway, the Tenth National Bank, and the New-York Printing Company, as well as proprietor of the Metropolitan Hotel.
Tweed was elected to the United States House of Representatives in 1852, and the New York City Board of Advisors in 1856. In 1858, Tweed became the "Grand Sachem" of Tammany Hall. He was elected to the New York State Senate in 1867.
Tweed was convicted for stealing between $40 million and $200 million (based on the inflation or devaluation rate of the dollar since 1870 of 2.7%, this is between 1.5 and 8 billion 2009 dollars) from New York City taxpayers through political corruption. He died in the Ludlow Street Jail.