- Jan 1 Union of Socialist Soviet Republics established
- Jan 1 Britain's Railways are grouped into the Big Four: LNER, GWR, SR, and LMSR.
- Jan 1 9th Rose Bowl: Southern California beats Penn State, 14-3
- Jan 2 Ku Klux Klan surprise attack on black residential area Rosewood Florida, 8 killed (compensation awarded in 1995)
- Jan 4 1st broadcast of "Barn Dance Show" (WBAP - Fort Worth Texas)
- Jan 7 Baltimore Sun warns of Ku Klux Klan
- Jan 8 Typography strike in Amsterdam
- Jan 9 Juan de la Cierva makes 1st autogiro flight, Spain
- Jan 9 Swaraj political party founded in India with Chittaranjan Das as president and Motilal Nehru its secretary
- Jan 10 Last US troops leave Rhineland (Germany)
- Jan 10 Lithuania seizes & annexes country of Memel
- Jan 11 1st Dutch Dada-evening (Theo Van Doesburg & Kurt Schwitters)
- Jan 11 French & Belgian troops occupy Ruhr to collect reparations
Event of Interest
Jan 13 Taking advantage of the chaotic condition of Germany, Hitler stages a demonstration of 5000 storm troopers and denounces the 'November crime'
Adolf Hitler
Agreement of Interest
Jan 19 UK Chancellor of the Exchequer Stanley Baldwin and US Secretary of the Treasury Andrew Mellon agree to reschedule repayment of Britain's $4.5 billion war debt over 62 years
Andrew Mellon
Stanley Baldwin
- Jan 23 Taxi strike in Amsterdam begins (through March 9th)
- Jan 24 Aztec Ruins National Monument in New Mexico established
- Jan 25 NVV donates 100,000 guilders to mine workers of Ruhrgebied
- Jan 28 Demonstration against a Dutch University in Ghent
- Jan 29 1st flight of autogiro (Juan de la Cierva, Madrid Spain)
- Jan 31 Montreal Canadiens beat Hamilton Tigers, 5-4 at the Mount Royal Arena, Montreal; first penalty-free game played in NHL history