- Oct 1 The watch company founded in 1850 in Roxbury by Aaron Lufkin Dennison relocates to Waltham, Massachusetts, to become the Waltham Watch Company, a pioneer in the American System of Watch Manufacturing.
- Oct 6 The Great Fire of Newcastle and Gateshead started shortly after midnight, leading to 53 deaths and hundreds injured.
- Oct 9 The siege of Sevastopol begins during the Crimean War
- Oct 10 US Assay Office in NYC, New York opens
- Oct 12 Lincoln University founded in Pennsylvania as Ashmun Institute
- Oct 17 French and British forces bombard Sevastopol for the first time during the Crimean War
- Oct 23 English newspaper "The Times" gives precise British positions in Crimea during Crimean War
Oct 25 The infamous "Charge of the Light Brigade" during the Battle of Balaclava in the Crimean War results in over 100 killed
- Oct 25 Prince Menshikov of Crimea occupies British base at Balaclava