Most of the story takes place on the ranch.
The workers live together in a bunkhouse, a long room lined with beds like an army barracks. They use rough burlap sacking stuffed with straw as their mattresses, and George worries that there may be bed bugs. Although most of the workers keep to themselves and are suspicious of other men, they will gather and talk in the bunkhouse and play cards there in the evening. When the weather is nice they also play horseshoes outside.
Crooks, the only black man on the ranch, does not enjoy the luxury of companionship. At this time racial segregation was widespread across the United States, and Crooks is forced to live on his own in a separate bedroom attached to the barn.
Curley, Curley's father, and Curley's new wife live in the main house at the ranch. This is a lonely place for Curley's wife, who is expected to stay inside, alone, all day.
Some photographs of ranch life in the 1930s:
The beginning and end of the story take place in the same location, a beautiful shaded river pool near the ranch. This is an idyllic place that illustrates how life can be beautiful and cruel at the same time (e.g. the periscope-like water snake and the heron that eats it).
Of Mice and Men is set near Soledad, California, in the Salinas Valley. The Salinas River flows through the valley, and the Gabilan Mountains rise above it.
In the 1930s, the United States, like the rest of the world, suffered the Great Depression. This was a time of great hardship for most people, when luxuries were scarce and ordinary people had to struggle for everything they had. Crop prices dropped by 60% and rural areas began to decline. Many people from the worst hit areas (the Great Plains and the South) migrated to more prosperous places like California. This put a huge strain on both migrant and host populations, as portrayed in John Steinbeck's The Grapes of Wrath.
During the 1930s prejudice based on race was very common. Racial segregation was widespread, with black people expected to live separately, sit separately on buses, drink from different water fountains, enter buildings by different entrances and so on. Hard-pressed people were ready to turn on each other, with lynchings and mob justice dangerously frequent, particularly against anyone seen as different. This is why the book's characters, especially Crooks and George (on behalf of Lennie) are so suspicious around others. George and Lennie have already fled from one lynch mob in Weed, CA.
Attitudes to women were still very conservative in rural 1930s America, despite the progress made by the feminist movement. Women were now allowed to vote, but in most places they were still expected to remain within the home and take on a domestic role. They were supposed to remain chaste and demure, and a woman who was seen to 'flirt' around men or to take her beauty regime too seriously might be looked on with disgust, as Curley's wife is.
In 1927 sound was introduced to films, and then in 1930 the first colour films appeared. Hollywood entered a Golden Age, with many great classics produced. This is the industry Curley's wife dreams of working in; at the time, as now, it would have seemed incredibly glamorous and full of possibility.