Tammany Hall was an organization based in New York City which became famous for the extent of its political corruption. Between 1854 and 1934, Tammany Hall essentially controlled Democratic party politics in New York City, and it had huge influence over the city's policies and politics. One of the most iconic figures in the history of Tammany Hall is Boss Tweed, a leader of the organization who practiced such widespread corruption that the city attempted to reform Tammany Hall; the organization was so powerful, however, that it managed to endure for decades after the fall of Boss Tweed.

The roots of Tammany Hall lie in the late 1700s, when numerous social organizations were springing up all over the newly-founded United States. The Tammany Society was initially a fraternal organization run along the lines of a social club, but in the 1830s, the Society started getting much more political in nature, and it came to be known as Tammany Hall in a reference to the headquarters of the organization. By the 1850s, Democrats in New York City knew that they would not get elected without the support of Tammany Hall, and the organization's influence also extended into state politics, as well.

Leaders at Tammany Hall used an assortment of techniques to consolidate and maintain their social and political power. One extremely useful tool for Tammany Hall was immigrants, especially Irish immigrants. The organization helped immigrants get their feet in the New World, in return for unquestioning political support. Certain members of the immigrant community were hand-picked for their potential, and groomed for positions in Tammany Hall and New York City politics, while immigrant communities benefited from things like health care, public fountains, and free arts performances sponsored by Tammany Hall.

Tammany Hall also used money, often in very high places, to ensure that it maintained a stranglehold on politics. Boss Tweed infamously set up the Tweed Ring, defrauding the City of New York for millions of dollars through the use of inflated contracts, and he in turn used this money to line his pockets and to support the efforts of Tammany Hall. Furthermore, politicians who chose to go against Tammany Hall would quickly find themselves out of the running as a result of the economic and political clout of the organization, leading many to reluctantly join Tammany Hall in order to accomplish their goals, and this consolidated power even further.

By the 1930s, the power of Tammany Hall was starting to seriously wane, as a result of changing political and social mores. However, the organization remained active until the 1960s, even playing a role in several Presidential elections of the 20th century before it finally petered out altogether, making way for a new host of political societies, organizations, and lobbyists.