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 (behind CBS's Gunsmoke), 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 (at various times) Guy Williams, David Canary, Mitch Vogel and Tim Matheson. The show is known for presenting pressing moral dilemmas.

Though not familiar stars in 1959, the cast quickly became favorites of the first television generation. The order of billing at the beginning of the broadcast appeared to be shuffled randomly each week, with no relation whatsoever to the current episode featured that week.

This section includes characters who will appear or have appeared in at least one season of the series.

Ben Cartwright is the thrice-widowed patriarch of the family. He originated in New England, where he was a seaman under the tutelage of one Abel Stoddard. His first wife was Abel's daughter Elizabeth, and they had one son, Adam. After his wife's death, he and his son traveled to Illinois, where he married his second wife, Inger Borgstrom, and continued west. His second son, Eric, or Hoss, was born in Nebraska on a wagon train. Upon reaching the Ash Hollow station, a fight with Indians occurred, and Inger was killed by an arrow. Ben and his sons then continued west, reaching Nevada, and through much hard work established the Ponderosa Ranch. On a trip to New Orleans to sell beaver pelts, Ben met and married Marie de Marigny, his third and final wife, and they had one son, Joseph, known as "Little Joe." Marie was killed after being thrown from a horse when Joe was 5 years old.

Early in the show's history, Ben recalls each of his late wives in flashback episodes. A standard practice with most Westerns was to introduce some romance but avoid matrimony. Few media cowboys had on-screen wives. Any time one of the Cartwrights seriously courted a woman, she died from a malady, was abruptly slain, or left with someone else. Ben appears in all but fourteen Bonanza episodes. Ben was deceased in the three later Bonanza TV movies, as Lorne Greene died shortly before production of the first film began, even though he had signed up to reprise his role.

In 2007, a TV Guide survey listed Ben Cartwright as television's #2 favorite dad.

Ben is portrayed by Lorne Greene, who was 44 years old at the beginning of the series while Pernell Roberts and Dan Blocker, who portrayed two of his sons, were both 31, only thirteen years younger.

The eldest son, Adam, is an architectural engineer with a university education. Adam built the impressive ranch house.