Tom Sawyer's America is, more than anything else, small. All he really knows is St. Petersburg, Missouri. And for him, for Twain and for us, that's fine. In The Adventures of Tom Sawyer, America is in the details, in the way the townspeople talk, in the look of things. When America shows up – as it does, in the person of a senator – it's met with disappointment. Not because there's anything wrong with it, really, but because, for Tom, it's not as incredibly grand and fantastic as he thought it would be.
Twain's America is one where civilization is not completely established, where disorder and wildness linger around the edges.
Twain captures the spirit of America on the page via small, wry observations; his America is not one of waving flags and soaring eagles, but of small-town details and eccentricities.