[3] The film tells the story of the Joads, an Oklahoma family of sharecroppers, who, after losing their farm to increased mechanization during the Great Depression in the 1930s, become migrant workers, and end up in California.

The motion picture details their arduous journey across the United States as they travel to California in search of work and opportunities for the family members, and features cinematography by Gregg Toland.

After driving awhile, they arrive at the Farmworkers' Weedpatch Camp ("Wheat Patch"), a clean facility run by the Department of Agriculture, complete with indoor toilets and showers, which the Joad children have never seen before.

Later, at one of the weekly Saturday night dances held at the Wheat Patch, a group of strangers arrive to instigate a riot as a pretext for local law enforcement to storm the camp and arrest the leaders.

The camp committee men have anticipated this and subdue the strangers when they attempt to start a fight, leaving the law no choice but to abort their plan.

When police officers arrive looking for the murderer of the guard Tom killed, he decides to leave, telling his mother that he plans to carry on Casy's mission by fighting for workers' rights.

[citation needed] Also, the producers decided to tone down Steinbeck's political references, such as eliminating a monologue using a land owner's description of "reds" as anybody "that wants thirty cents an hour when we're payin' twenty-five," to show that under the prevalent conditions that definition applies to every migrant worker looking for better wages.

The film emphasizes Ma Joad's pragmatic, forward-looking way of dealing with their situation despite Tom's departure, as it concludes with her spiritual "We're the people" speech.

[citation needed][7] Ivy and Sairy Wilson, who attend to Grandpa's death and travel with the Joads until they reach California, are left out of the movie entirely.

[8] In the film, most of the Joad family members are either reduced to background characters – in the case of Al, Noah, and Uncle John – or to being the focus of only one or two relatively minor scenes – like Rose-of-Sharon and Connie.

Due to the red-baiting common to the era, Darryl Zanuck sent private investigators to Oklahoma to help him legitimize the film.

[9] Critic Roger Ebert believed that World War II also helped sell the film's message, as Communism received a brief respite from American demonizing during that period.

Some of the filming locations include: Oklahoma City, McAlester, Bridgeport, and Sayre, all in Oklahoma; Gallup, Laguna Pueblo, Santa Rosa, and San Jon, all in New Mexico; Thousand Oaks,[11] Lamont, Needles, Vidal Junction, and the San Fernando Valley, all in California; Topock and the Petrified Forest National Park, both in Arizona.

[14] Frank Nugent of The New York Times wrote: "In the vast library where the celluloid literature of the screen is stored there is one small, uncrowded shelf devoted to the cinema's masterworks, to those films which by dignity of theme and excellence of treatment seem to be of enduring artistry, seem destined to be recalled not merely at the end of their particular year but whenever great motion pictures are mentioned.

Cleared of excrescences, the residue is a great human story which made thousands of people, who damned the novel's phony conclusions, read it.

"[17]A review in Variety reported, "Here is outstanding entertainment, projected against a heart-rending sector of the American scene," concluding, "It possesses an adult viewpoint and its success may lead other producers to explore the rich field of contemporary life which films long have neglected and ignored.

Its beauty is of the sort found in the art of Burchfield, Benton and Curry, as the landscape and people involved belong to the world of these painters.

It also includes various supplements: an A&E Network biography of Daryl F. Zanuck, outtakes, a gallery, Franklin D. Roosevelt lauds motion pictures at Academy featurette, Movietone news: three drought reports from 1934, etc.