Based on the lives of Albert and Thyra Johnston, who lived in New Hampshire in the 1930s and '40s.
Dr. Carter is shown traveling by US Coast Guard boat from Portsmouth, NH, to the Isle of Shoals, about six nautical miles from the city harbor. However, when the boat arrives at its destination it is actually the Cape Neddick Lighthouse station (a.k.a. the Nubble) just off the coast from York, ME. The house the doctor is shown entering is the lighthouse keeper's residence.
Parker Fennelly (Alvin Tupper) appeared regularly on radio's "Fred Allen Show" as the character "Titus Moody." His first line was almost always "Howdy Bub!" It is also his first line in this film.
Lost Boundaries (1949) is an American film starring Beatrice Pearson, Mel Ferrer (in his first leading role), and Susan Douglas Rubes. It is based on William L. White's story of the same title, a nonfiction account of Dr. Albert C. Johnston and his family, who passed for white while living in New England in the 1930s and 1940s. The film won the 1949 Cannes Film Festival award for Best Screenplay. The use of white actors in the film's leading black roles proved controversial. The film was banned in Atlanta, Georgia, and Memphis, Tennessee.