Of Mice and Men takes place in central California, a landscape with hills and expansive ranches, with trees on the hills but no forests. The opening section of the book offers the best description of physical environment.
"Of Mice and Men opens with a physical description of the topography of the Central Valley of California. "A few miles south of Soledad," the Salinas river winds through an idyllic scene of yellow sands, golden foothills, and deer that come to the shore to drink at night."
The ranch itself is not given a detailed description beyond the loosely defined layout of the ranch buildings: a bunk house, a barn, and a main house.