1839 1840 1841 - 1842 - 1843 1844 1845
1810s 1820s 1830s - 1840s - 1850s 1860s 1870s
Events of 1842
- February 7 – Battle of Debre Tabor: Ras Ali Alula, Regent of the Emperor of Ethiopia, defeats warlord Wube Haile Maryam of Semien.
- March 2 – Gaylad, ridden by Tom Olliver, wins the Grand National at Aintree Racecourse.
- March 5 – Mexican troops led by Rafael Vasquez invade Texas, briefly occupy San Antonio, and then head back to the Rio Grande. This is the first such invasion since the Texas Revolution.
- March 9 – Giuseppe Verdi's third opera Nabucco premieres in Milan; its success establishes Verdi as one of Italy's foremost opera writers.
- March 30 – Anesthesia is used for the first time in an operation (Dr. Crawford Long performed the operation using ether).
- March 31 – Middleton Junction and Oldham Branch Railway line opened up to Werneth in North West England.
- May 8 – Versailles train crash: Two trains collide near Paris and catch fire, killing 59.
- May 19 – Dorr Rebellion: Militiamen supporting Thomas Wilson Dorr attack the arsenal in Providence, Rhode Island but are repulsed.
- June 4 – In South Africa, hunter Dick King rides into a British military base in Grahamstown to warn that the Boers have besieged Durban (he had left 11 days earlier). The British army dispatches a relief force.
- June 20 – Anselmo de Andrade, Portuguese economist and politician born in Vila Real de Santo António.
- July 13 – The Tri-Kap fraternity is founded at Dartmouth College. It is the oldest local fraternity in the nation.
- August 4 – The Armed Occupation Act is signed, providing for the armed occupation and settlement of the unsettled part of the Peninsula of East Florida.
- August 9 – The Webster-Ashburton Treaty is signed, establishing the United States–Canada border east of the Rocky Mountains.
- August 10 – The Mines Act 1842 becomes law, prohibiting underground work for all women and boys under 10 years old in England.
- August 29 – The Treaty of Nanking ends the First Opium War and establishes Hong Kong as a British colony.
- October 29 – The Iberian Peninsula is struck by a category 2 hurricane.
- December 20 – The Citadel, The Military College of South Carolina is established.