The Whiskey Ring took place from 1871 to 1876 centering in St. Louis during the presidency of Ulysses S. Grant. The ring was an American scandal, broken in May 1875, involving the diversion of tax revenues in a conspiracy among government agents, politicians, whiskey distillers, and distributors. Whiskey distillers bribed officials from the U. S. Department of the Treasury to increase profits and evade taxes. Grant's Justice Department prosecuted members of Grant's own Republican Party who were part of the Ring. The kingpin of the Whiskey Ring was the notorious General John McDonald, whom Grant had appointed Revenue Collector of Missouri District in 1869. Under the leadership of Grant's Secretary of Treasury, Benjamin Bristow, a reformer, the Ring was uncovered and broken up.

The presidency of Ulysses S. Grant began on March 4, 1869, when Ulysses S. Grant was inaugurated as the 18th president of the United States, and ended on March 4, 1877. The Reconstruction era took place during Grant's two terms of office. The Ku Klux Klan caused widespread violence throughout the South against African Americans. By 1870, all former Confederate states had been readmitted into the United States and were represented in Congress; however, Democrats and former slave owners refused to accept that freedmen were citizens who were granted suffrage by the Fifteenth Amendment, which prompted Congress to pass three Force Acts to allow the federal government to intervene when states failed to protect former slaves' rights. Following an escalation of Klan violence in the late 1860s, Grant and his attorney general, Amos T. Akerman, head of the newly created Department of Justice, began a crackdown on Klan activity in the South, starting in South Carolina, where Grant sent federal troops to capture Klan members. This led the Klan to demobilize and helped ensure fair elections in 1872.