1st January » The Cobble Hill Tunnel in Brooklyn, New York City called New York, New York is completed.
29th January » "The Raven" is published in the 'New York Evening Mirror', the first publication with the name of the author, Edgar Allan Poe
1st March » President of the United States known as President John Tyler signs a bill authorizing the United States to annex the Republic of Texas.
3rd March » Florida is admitted as the 27th U.S. state.
11th March » The Flagstaff War: Unhappy with translational differences regarding the Treaty of Waitangi, chiefs Hone Heke, Kawiti and Māori people e.g Māori tribe members chop down the British flagpole for a fourth time and drive settlers out of Kororareka, New Zealan
6th August » The Russian Geographical Society is founded in Saint Petersburg, Russia.
28th August » The first issue of 'Scientific American' magazine is published.
23rd September » The New York Knickerbockers known as Knickerbockers Baseball Club, the first baseball team to play under the modern rules, is founded in New York.
9th October » The eminent and controversial Anglicanism known as Anglican, John Henry Newman, is received into the Roman Catholic Church.
10th October » In Annapolis, Maryland, the Naval School (later renamed the United States Naval Academy) opens with 50 midshipman students and seven professors.
13th October » A majority of voters in the Republic of Texas approve a proposed constitution that, if accepted by the Congress of the United States known as U.S. Congress, will make Texas a U.S. state.
20th November » Anglo-French blockade of the Río de la Plata: Battle of Vuelta de Obligado.
2nd December » Manifest Destiny: In a State of the Union address named State of the Union message, U.S. President James K. Polk proposes that the United States should aggressively expand into the West.
27th December » Diethyl ether known as Ether anesthetic is used for childbirth for the first time by Dr. Crawford Long in Jefferson, Georgia.
29th December » In accordance with International Boundary delimitation, United States annexes the Republic of Texas, following the manifest destiny doctrine. The Republic of Texas, which had been independent since the Texas Revolution of 1836, is thereupon admitted as
6th February » Isidor Straus, German-American businessman and politician (d. 1912)
15th February » Elihu Root, American lawyer and politician, 38th United States Secretary of State, Nobel Peace Prize called Nobel Prize laureate (d. 1937)
16th February » George Kennan (explorer) or George Kennan, American explorer (d. 1924)
25th February » George Reid (Australian politician) e.g George Reid, Australian politician, 4th Prime Minister of Australia (d. 1918)
3rd March » Georg Cantor, German mathematician (d. 1918)
7th June » Leopold Auer, Hungarian violinist, composer, and conductor (d. 1930)
9th June » Gilbert Elliot-Murray-Kynynmound, 4th Earl of Minto, English politician, 36th Governor-General of India (d. 1914)
9th June » Frank Norton, American baseball player (d. 1920)
18th June » Charles Louis Alphonse Laveran, French physician and parasitologist, Nobel Prize in Physiology or Medicine known as Nobel Prize laureate (d. 1922)
26th August » Mary Ann Nichols, English victim of Jack the Ripper (d. 1888)
27th August » Ödön Lechner, Hungarian architect, designed the Museum of Applied Arts (Budapest) known as Museum of Applied Arts and the Church of St. Elisabeth (Bratislava) called Church of St. Elisabeth (d. 1914)
27th August » Friedrich Martens, Estonian-Russian historian, lawyer, and diplomat (d. 1909)
24th September » Nikolai Anderson, Estonian philologist and author (d. 1905)
8th October » Salomon Kalischer, German pianist, composer, and physicist (d. 1924)
21st October » Will Carleton, American poet (d. 1912)
28th October » Zygmunt Florenty Wróblewski, Polish physicist and chemist (d. 1888)
3rd November » Edward Douglass White, American lawyer, jurist, and politician, 9th Chief Justice of the United States (d. 1921)
4th November » Vasudev Balwant Phadke, Indian activist (d. 1883)
10th November » John Sparrow David Thompson, Canadian lawyer, judge, and politician, 4th Prime Minister of Canada (d. 1894)
22nd November » Aleksander Kunileid, Estonian composer (d. 1875)
25th November » José Maria de Eça de Queirós, Portuguese-French journalist and author (d. 1900)
9th December » Joel Chandler Harris, American journalist and author (d. 1908)
12th December » Bruce Price, American architect, designed the American Surety Building and Bank of the Metropolis (d. 1903)