| 61 | January 1 | Event | 1911 – Northern Territory is separated from South Australia and transferred to Commonwealth control. |
| 62 | January 1 | Event | 1912 – The Republic of China is established. |
| 63 | January 1 | Event | 1913 – The British Board of Censors is established. |
| 64 | January 1 | Event | 1916 – German troops abandon Yaoundé and their Kamerun colony to British forces and begin the long march to Spanish Guinea. |
| 65 | January 1 | Event | 1920 – The Belorussian Communist Organisation is founded as a separate party. |
| 66 | January 1 | Event | 1923 – Britain's Railways are grouped into the Big Four: LNER, GWR, SR, and LMS. |
| 67 | January 1 | Event | 1927 – The Cristero War begins in Mexico. |
| 68 | January 1 | Event | 1927 – Turkey adopts the Gregorian calendar: December 18, 1926 (Julian), is immediately followed by January 1, 1927 (Gregorian). |
| 69 | January 1 | Event | 1928 – Boris Bazhanov defects through Iran. He is the only assistant of Joseph Stalin's secretariat to have defected from the Eastern Bloc. |
| 70 | January 1 | Event | 1929 – The former municipalities of Point Grey, British Columbia and South Vancouver, British Columbia are amalgamated into Vancouver. |
| 71 | January 1 | Event | 1932 – The United States Post Office Department issues a set of 12 stamps commemorating the 200th anniversary of George Washington's birth. |
| 72 | January 1 | Event | 1934 – Alcatraz Island becomes a United States federal prison. |
| 73 | January 1 | Event | 1934 – Nazi Germany passes the "Law for the Prevention of Genetically Diseased Offspring". |
| 74 | January 1 | Event | 1937 – Safety glass in vehicle windscreens becomes mandatory in the United Kingdom. |
| 75 | January 1 | Event | 1939 – Sydney, Australia, swelters in 45 ˚C (113 ˚F) heat, a record for the city. |
| 76 | January 1 | Event | 1942 – The Declaration by United Nations is signed by twenty-six nations. |
| 77 | January 1 | Event | 1945 – World War II: In retaliation for the Malmedy massacre, U.S. troops massacre 30 SS prisoners at Chenogne. |
| 78 | January 1 | Event | 1945 – World War II: The German Luftwaffe launches Operation Bodenplatte, a massive, but failed attempt to knock out Allied air power in northern Europe in a single blow. |
| 79 | January 1 | Event | 1947 – The American and British occupation zones in Germany, after World War II, merge to form the Bizone, which later (with the French zone) became part of West Germany. |
| 80 | January 1 | Event | 1947 – The Canadian Citizenship Act 1946 comes into effect, converting British subjects into Canadian citizens. Prime Minister William Lyon Mackenzie King becomes the first Canadian citizen. |
| 81 | January 1 | Event | 1948 – The British railway network is nationalized to form British Railways. |
| 82 | January 1 | Event | 1948 – The Constitution of Italy comes into force. |
| 83 | January 1 | Event | 1949 – United Nations cease-fire takes effect in Kashmir from one minute before midnight. War between India and Pakistan stops accordingly. |
| 84 | January 1 | Event | 1949 –Tokelau becomes part of New Zealand. |
| 85 | January 1 | Event | 1950 – Standard practice uses this day as the origin of the age scale Before Present |
| 86 | January 1 | Event | 1954 – NBC makes the first coast-to-coast NTSC color broadcast when it telecast the Tournament of Roses Parade, with public demonstrations given across the United States on prototype color receivers. |
| 87 | January 1 | Event | 1956 – Sudan achieves independence from Egypt and the United Kingdom. |
| 88 | January 1 | Event | 1956 – A new year event causes panic and stampedes at Yahiko Shrine, Yahiko, Niigata, Japan, killing at least 124 people. |
| 89 | January 1 | Event | 1957 – George Town, Penang becomes a city by a royal charter granted by Elizabeth II. |
| 90 | January 1 | Event | 1957 – An Irish Republican Army (IRA) unit attacks Brookeborough RUC barracks during Operation Harvest two IRA volunteers killed. |