This Other Eden by Paul Harding

From the Pulitzer Prize–winning author of Tinkers, a novel inspired by the true story of Malaga Island, an isolated island off the coast of Maine that became one of the first racially integrated towns in the Northeast.
In 1792, formerly enslaved Benjamin Honey and his Irish wife, Patience, discover an island where they can make a life together. Over a century later, the Honeys' descendants and a diverse group of neighbors are desperately poor, isolated, and often hungry, but nevertheless protected from the hostility awaiting them on the mainland.
During the tumultuous summer of 1912, Matthew Diamond, a retired, idealistic but prejudiced schoolteacher-turned-missionary, disrupts the community's fragile balance through his efforts to educate its children. His presence attracts the attention of authorities on the mainland who, under the influence of the eugenics-thinking popular among progressives of the day, decide to forcibly evacuate the...