What is the importance of "Dirt Island" in the novel, The Queen of Dirt Island?

Dirt Island is the plot of land owned by Eileen's parents. Her grandfather and father inherited the property. The locals began referring to it as Dirt Island because, Eileen tells Saoirse in "Repose," "everyone was jealous of it" (49). When Eileen and Richard were growing up, they often battled for their rights to the little island "in the middle of a small lake" where they would play (49). As adults, these battles of the land become more real. Indeed, Eileen leaves the property after getting pregnant and marrying Saoirse's father. Her family has rejected her, and so she stays away until her mother's funeral. When her father dies not long later, Eileen inherits the most valuable portion of the land, which Richard is desperate to acquire from her. Eileen retains her right to the land for as long as she can.