Riders of the Purple Sage takes place in Southern Utah during a point in history when members of the Mormon faith were still the majority of settlers in the area. Members of the Mormon faith began moving into Utah in 1847, shortly after the death of their founder, John Smith. The novel opens in 1871, just 24 years later. As a result, the communities of Utah are still primarily made up of members of the Mormon faith in the novel. As the daughter of the man who founded the original settlement at Cottonwoods, Jane Withersteen lives with many great expectations. As a single, Mormon woman, she is expected to marry a Mormon man. However, Jane is sympathetic to the non-Mormon people in the area and has gone out of her way to help them. She has even engaged in a relationship with Bern Venters, a non-Mormon man. Mormon leaders disapprove and wage war on Jane to convince her to marry Mormon man and church leader, Elder Tull.

Throughout the novel, Jane is told to behave in ways that her community believes are more suited to her position as a Mormon woman.