The Adventures of Huckleberry Finn

Land: The land, in Huck Finn, largely represents the bondage and cruelty of American civil society.  To Jim, the land means captivity in slavery.  To Huck, the land comes to symbolize bondage of thought and behavior exuded by the religious-minded Miss Watson and the Widow Douglas. 

Mississippi River/Raft: Conversely, the Mississippi River, more than any other physical entity in the novel, symbolizes freedom, both for Jim and Huck.  The pair can only find safety and peace of mind on the river; whenever they step onto land, they find themselves getting into trouble.

Twain's characters: Twain also uses many of his main characters to represent certain characteristic qualities of Americans.  Huck, for example, is the typical American frontiersman: he's shrewd, even manipulative at times, and above all, he's a realist.  Tom, though he possesses many of the same qualities, is less of a realist, but instead tries to romanticize his world.  Huck's pap has what Tocqueville describes as a depraved love of equality.  He symbolizes the corruption of humanity and the depravity of those who live outside of civilization.  Huck's pap is a perfect contrast to the Widow Douglas and Miss Watson, who epitomize the civility of religious women in America.