Bonanza is an American Western television series that ran on NBC from September 12, 1959, to January 16, 1973. Lasting 14 seasons and 431 episodes, Bonanza is NBC's longest-running Western, the second-longest-running Western series on U.S. network television, and one of the longest-running, live-action American series. The show continues to air in syndication. The show is set in the 1860s and centers on the wealthy Cartwright family, who live in the vicinity of Virginia City, Nevada, bordering Lake Tahoe. The series initially starred Lorne Greene, Pernell Roberts, Dan Blocker and Michael Landon and later featured Guy Williams, David Canary, Mitch Vogel and Tim Matheson. The show is known for presenting pressing moral dilemmas.

Television Westerns are programs with settings in the later half of the 19th century in the American Old West, Western Canada and Mexico during the period from about 1860 to the end of the so-called "Indian Wars". More recent entries in the Western genre have used the neo-Western subgenre, placing events in the modern day, or the space Western subgenre but still draw inspiration from the outlaw attitudes prevalent in traditional Western productions.