There is a plethora of great American literature, I could not create a list of less than 20. However, I focused less on the popularity of a novel/author and more on a variety and depth of “American ” (U.S.) content/concepts and ideas/ideals etc. Literature that focuses on the history, growth, and culture of our nation.
So, I was able to narrow it down…

Here is my list of quintessential American literary works:

PART II of II

The Things They Carried 

by Tim O’Brien
A classic, life-changing meditation on war, memory, imagination, and the redemptive power of storytelling

Rated 4.4 on amazon.com

Gone With the Wind
by Margaret Mitchell
Widely considered The Great American Novel, and often remembered for its epic film version, Gone With the Wind explores the depth of human passions with an intensity as bold as its setting in the red hills of Georgia. A superb piece of storytelling, it vividly depicts the drama of the Civil War and Reconstruction.

Rated 4.6 on amazon.com

The Catcher in the Rye
By J.D. Salinger
A controversial novel originally published for adults, it has since become popular with adolescent readers for its themes of teenage angst and alienation.
Wikipedia

Rated 4.0 on amazon.com

To Kill a Mockingbird
By Harper Lee
The unforgettable novel of a childhood in a sleepy Southern town and the crisis of conscience that rocked it, To Kill A Mockingbird became both an instant bestseller and a critical success when it was first published in 1960. It went on to win the Pulitzer Prize in 1961 and was later made into an Academy Award-winning film, also a classic.

Rated 4.7 on amazon.com

Moby Dick

By Melville
Moby-Dick; or, The Whale is a novel by American writer Herman Melville, published in 1851 during the period of the American Renaissance.

 
Rated 4.7 on amazon.com

The Crucible

By Arthur Miller
Based on historical people and real events, Arthur Miller’s play uses the destructive power of socially sanctioned violence unleashed by the rumors of witchcraft as a powerful parable about McCarthyism.

Rated 4.1 on amazon.com

Civil Disobedience
Henry David Thoreau
An essay by American transcendentalist Henry David Thoreau that was first published in 1849. In it, Thoreau argues that individuals should not permit governments to overrule or atrophy their consciences, and that they have a duty to avoid allowing such acquiescence to enable the government to make them the agents of injustice. Thoreau was motivated in part by his disgust with slavery and the Mexican–American War.

Rated 4.5 on amazon.com

Of Mice and Men

By John Steinbeck
Published in 1937, it tells the story of George Milton and Lennie Small, two displaced migrant ranch workers, who move from place to place in California in search of new job opportunities during the Great Depression in the United States.
Rated 4.4 on amazon.com

The Sound and The Fury
By William Faulkner
The tragedy of the Compson family, featuring some of the most memorable characters in literature: beautiful, rebellious Caddy; the manchild Benjy; haunted, neurotic Quentin; Jason, the brutal cynic; and Dilsey, their black servant. Their lives fragmented and harrowed by history and legacy, the character’s voices and actions mesh to create what is arguably Faulkner’s masterpiece and  one of the greatest novels of the twentieth century.

Rated 3.9 on amazon.com