In Dubious Battle, like most of Steinbeck's early work, is set in northern and central California.  When readers are first introduced to Jim, he is enlisting with the Party in what is only referred to as "the city."  Most of the novel's action takes place in Torgas Valley, a fictional agricultural valley located in central California.  Critics have attempted to map the actual location of Torgas Valley, noting that the city is possibly San Jose and that the Torgas Valley is likely modeled after Tulare County, site of a peach strike on the Tagus Ranch in 1933.   Biographer Jackson Benson demonstrates identifying the actual location is problematic since Jim and Mac not only travel on fictionalize railroad lines, but "[…] there is no self-contained little valley anywhere near Tulare" and "[…] the climate in the Central Valley is too temperate for apple growing" (299).  Rather, Benson argues, Steinbeck likely combined incidents from two strikes, the peach strike in Tulare County and a cotton strike that occurred in 1933 as well, the events of which he had first hand accounts from two labor agitators, Cicil McKiddy and Pat Chambers.

In response to critics' estimations about the location, Steinbeck replied, "I have usually avoided using actual places to avoid hurting feelings, for, although I rarely use a person or a story as it is—neighbors love only too well to attribute them to someone. …as for the valley in In Dubious Battle—it is a composite valley as it is a composite strike" (qtd. in Benson 298).  More important than pinpointing the actual location is that the similarities between the novel's events and various strikes in California attest to the poor working conditions for farm labors that were obviously rampant there in the 1930s.  The underhanded deeds of the Growers' Association and vigilantes in the Torgas Valley were unfortunately all too real in many California towns, as Steinbeck witnessed first hand while traveling and collecting stories from labor organizers and migrant workers during this period.  The events of the novel could have taken place almost anywhere in central California as perpetuating injustice against migrant workers seemed common place.  Steinbeck's indignation over that fact would ultimately lead to the writing of his masterpiece, The Grapes of Wrath (1939), only a few years after the publication of In Dubious Battle.