|Decades:||1890s - 1900s - 1910s - 1920s - 1930s - 1940s - 1950s|
|Centuries:||19th century - 20th century - 21st century|
Events of unspecified date
- Criminal gangs exercise substantial power in the city of Chicago. This period will be the subject of the book Chicago Mobs of the Twenties, which will later influence the inhabitants of Sigma Iotia II.
- Wesley Crusher transports William T. Riker to a jazz club in Illinois.
- The Roaring 20s era of Earth's American history. The era led into the Great Depression of the 1930s. In certain frames of reference revealed to humanoid visitors, the Q Continuum resembled North America in the Roaring Twenties. (New Worlds, New Civilizations short story: "Beyond Horizons")