River of Earth is narrated by a young boy whose family, the Baldridges, lives in the mountains because his father works as a coal miner. When the mines are open, the family's situation is a great deal more secure—they have enough food—but when the mines are closed, they really struggle to feed themselves and their three children. To make matters a little worse for them, Brack Baldridge, the father, refuses to turn away members of his family who need a place to live and food to eat, and he likewise cannot bring himself to turn away people who come begging for food (even though it means less food in his own family's bellies). The baby of the family, Green, is sickly, and he eventually dies, in part, as a result of malnutrition.

The protagonist, whose name we don't learn, goes to school for a while, and then he goes to live with his grandmother, learning all about her life and children (his uncles). Alpha, the protagonist's mother, often tries to get her husband to stop coal mining and take up some other job, but he feels strongly that this is what he's meant to do in his life. He doesn't tend to listen to her much, though it is evident that they care about one another; there are just so many very pressing needs of their family. One gets the sense that they are doing the best they can in dire situations, but it always feels as though they are just a step or two away from going hungry. It's a very hand-to-mouth existence. In the end, Alpha has another baby.