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, and ranks overall as the second-longest-running western series on U.S. network television (behind CBS's Gunsmoke), and within the top 10 longest-running, live-action American series. ( from Wikipedia).