Is Jennifer Donnelly's, A Northern Light, a true story?

Yes, Jennifer Donnelly grew up on the outskirts of the Adirondacks hearing tales and ballads of the 1906 murder of Grace Brown, a pregnant nineteen-year-old drowned by her lover in Big Moose Lake. Donnelly's great-grandmother had been working at a hotel on the lake when the murder took place. Her firsthand account, reinforced by Donnelly's reading of Theodore Dreiser's novel concerning the same murder, stirred Donnelly's curiosity. A Northern Light is her story of Grace's life and death, created through reading Grace's letters and the transcripts of Chester Gillette's trial.