The Hillcrest Mystery is a 1918 silent film directed by George Fitzmaurice and starring Irene Castle. The film was released by Pathé Exchange in March 1918, only a month following the untimely death of Irene Castle's husband and dance partner, Vernon Castle in an airplane accident.
With no prints of The Hillcrest Mystery located in any film archives, it is considered a lost film. In February 2021, the film was cited by the National Film Preservation Board on their Lost U.S. Silent Feature Films list.