American television series that ran on the National Broadcasting Company (National Broadcasting Co., Inc.) (NBC) network from 1959 to 1973. Bonanza's 14 seasons and 440 episodes made it the second-longest-running western in broadcast history, after Gunsmoke.

Bonanza, the first western broadcast in colour, recounted the story of the Cartwrights, a fictional family of ranchers living in the mid-1800s, near Virginia City, Nev., an actual mining boomtown. The Cartwrights were an all-male family headed by Ben (played by Lorne Greene), thrice a widower with a son from each marriage: Adam (Pernell Roberts), Hoss (Dan Blocker), and Little Joe (Michael Landon). Adam, the eldest, was serious and responsible, while Hoss was gregarious and oafish, and Little Joe was rashly romantic. The plot in the early seasons often stemmed from personality conflicts between the brothers, but the show's drama eventually turned toward issues pertaining to mining and managing the Cartwright ranch, the Ponderosa. Often, the Cartwrights were called on to deal with threatening outsiders and to restore peace.

Although Bonanza adhered to many genre conventions, it appealed to general audiences by also avoiding some of those conventions. Whereas westerns often featured gunslingers roaming the prairie, the Cartwrights were landowners, tethered to the Ponderosa, and fixtures of the community. Rather than settle disputes solely through shoot-outs and show downs, the Cartwrights also employed diplomacy and dialogue.