* Tom Sawyer: The mischievous and adventurous protagonist of *The Adventures of Tom Sawyer* (1876).
* Huckleberry Finn: Tom Sawyer's best friend and the protagonist of *Adventures of Huckleberry Finn* (1885).
* Pudd'nhead Wilson: A clever detective in the novel *Pudd'nhead Wilson's Calendar* (1894).
* The Prince and the Pauper: Two boys, one rich and one poor, who switch places in the novel *The Prince and the Pauper* (1881).
Twain also created memorable characters in other works, such as:
* Josiah Clemens: The title character of *The Gilded Age* (1873)
* Becky Thatcher: Tom Sawyer's love interest in *The Adventures of Tom Sawyer*.
* Injun Joe: Tom Sawyer's nemesis in *The Adventures of Tom Sawyer*.
These characters have become iconic figures in American literature and continue to be enjoyed by readers of all ages.