1917 is a year in the 20th century.
- December 24: A young couple, Maurice and Lyda, kill themselves in a murder-suicide rather than be separated. They become ghosts and haunt the house they die in Maryland. (TXF: "How the Ghosts Stole Christmas")
- The US Espionage Act of 1917 becomes law. Many spies are arrested for working against America's interest and executed for at least 34 years. (TXF: "Musings of a Cigarette-Smoking Man")
- The United States fights in World War I, and many soldiers die over the course of the war. (TXF: "How the Ghosts Stole Christmas")
- A deadly strain of the flu virus attacks many people in the US. (TXF: "How the Ghosts Stole Christmas")