Who is the narrator, can she or he read minds, and, more importantly, can we trust her or him?
First Person (Central)—Howard and Tilly
Okay, so we have ourselves two first-person narrators. One's a way bigger player than the other, though, so let's start small and work from there.
Howard narrates the frame story, i.e., the first and last chapters. He tells readers about the summer he traveled to Grand Tower, Illinois, to meet his father's family, saying, "I ought to have kept a journal of the trip, but that's not the way of a fifteen-year-old boy" (1.15). The point of Howard's narration is mostly to set us up for Tilly's story, though. Tilly has to tell her story to someone, and Howard fits the bill.
We get into the meat of the book in Chapter 2 when Tilly takes the reins and doesn't hand them back to Howard until the end of Chapter 14. As she narrates, she also takes us back to 1861, telling Howard (and the reader) about how Delphine became a part of the Pruitt family. While Tilly is definitely a key player in the events of 1861 and narrates them from her perspective, like a good central narrator should, it's part of Tilly's character to turn her lens on those around her rather than dominating the story herself (more on this in her page in the "Characters" section). Thus, she often focuses her tale on others, especially Delphine. Consider this example:
How well I recall Delphine and me coming in from that damp evening, pulling off her bonnets. Calinda, treetop-tall, had her face to the fire and her skirts pinned up under an apron of Mama's. She was browning onions in the biggest skillet. Nearly stuck to her side was Cass, measuring paste out of a jar. (5.60)
Tilly is right in the action, but she lets us know what's going on with others, too. Like, a lot. Thanks, Tilly, for telling the story so thoroughly.