|Wikimedia Commons has media related to 1898.|
1898 (MDCCCXCVIII) was a common year starting on Saturday of the Gregorian calendar and a common year starting on Thursday of the Julian calendar, the 1898th year of the Common Era (CE) and Anno Domini (AD) designations, the 898th year of the 2nd millennium, the 98th year of the 19th century, and the 9th year of the 1890s decade. As of the start of 1898, the Gregorian calendar was 12 days ahead of the Julian calendar, which remained in localized use until 1923.
- January 1 – New York City annexes land from surrounding counties, creating the City of Greater New York as the world's second largest. The city is geographically divided into five boroughs: Manhattan, Brooklyn, Queens, The Bronx and Staten Island.
- January 13 – Novelist Émile Zola's open letter to the President of the French Republic on the Dreyfus affair, J'Accuse…!, is published on the front page of the Paris daily newspaper L'Aurore, accusing the government of wrongfully imprisoning Alfred Dreyfus and of antisemitism.
- February 12 – The automobile belonging to Henry Lindfield of Brighton rolls out of control down a hill in Purley, London, England, and hits a tree; thus he becomes the world's first fatality from an automobile accident on a public highway.
- February 15 – Spanish–American War: The USS Maine explodes and sinks in Havana Harbor, Cuba, for reasons never fully established, killing 266 men. The event precipitates the United States' declaration of war on Spain, two months later.
- April 5 – Annie Oakley promotes the service of women in combat situations, with the United States military. On this day, she writes a letter to President McKinley "offering the government the services of a company of 50 'lady sharpshooters' who would provide their own arms and ammunition should war break out with Spain." In the history of women in the military, there are records of female U.S. Revolutionary and Civil War soldiers who enlisted using male pseudonyms, but Oakley's letter represents possibly the earliest political move towards women's rights for combat service, in the United States military.
- April 22 – Spanish–American War: The United States Navy begins a blockade of Cuban ports and the USS Nashville captures a Spanish merchant ship.
- April 23 – Spanish–American War: A conference of senior Spanish Navy officers led by naval minister Segismundo Bermejo decide to send Admiral Pascual Cervera's squadron to Cuba and Puerto Rico.
- April 25 – Spanish–American War: The United States declares war on Spain; the U.S. Congress announces that a state of war has existed since April 21 (later backdating this one more day to April 20).
- April 25 – In Essen, German company Rheinisch-Westfälisches Elektrizitätswerk RWE is founded.
- April 26 – An explosion in Santa Cruz, California kills 13 workers, at the California Powder Works.
- May 1 – Spanish–American War – Battle of Manila Bay: Commodore Dewey destroys the Spanish squadron, in the first battle of the war, as well as the first battle in the Philippines Campaign.
- May 2 – Thousands of Chinese scholars and Beijing citizens seeking reforms protest in front of the capital control yuan.
- May 7–9 – Bava Beccaris massacre: Hundreds of demonstrators are killed, when General Fiorenzo Bava Beccaris orders troops to fire on a rally in Milan, Italy.
- May 8 – The first games of the Italian Football Federation are played, in which Genoa played against Torino.
- May 12 – Spanish–American War: The Puerto Rican Campaign begins, with the Bombardment of San Juan.
- May 27 – The territory of Kwang-Chou-Wan is leased by China to France, according to the Treaty of 12 April 1892, as the Territoire de Kouang-Tchéou-Wan, forming part of French Indochina.
- May 28 – Secondo Pia takes the first photographs of the Shroud of Turin and discovers that the image on the Shroud itself appears to be a photographic negative.
- July 1 – Spanish–American War: Battle of San Juan Hill – United States troops (including Buffalo Soldiers and Theodore Roosevelt's Rough Riders) take a strategic position close to Santiago de Cuba from the Spanish.
- July 3
- July 4 – En route from New York to Le Havre, the ocean liner SS La Bourgogne collides with another ship and sinks off the coast of Sable Island with the loss of 549 lives.
- July 7 – The United States annexes the Hawaiian Islands.
- July 9 – The Nationale Tentoonstelling van Vrouwenarbeid 1898 took place in The Hague and becomes a milestone for the Dutch women's movement.
- July 17 – Spanish–American War: Battle of Santiago Bay – Troops under United States General William R. Shafter take the city of Santiago de Cuba from the Spanish.
- July 18 – "The Adventures of Louis de Rougemont" first appear in The Wide World Magazine, as its August 1898 issue goes on sale.
- July 25 – Spanish–American War: The United States invasion of Puerto Rico begins, with a landing at Guánica Bay.
- August 12 – Spanish–American War: Hostilities end between American and Spanish forces in Cuba.
- August 13 – Spanish–American War: Battle of Manila – By prior agreement, the Spanish commander surrenders the city of Manila to the United States, in order to keep it out of the hands of Filipino rebels, ending hostilities in the Philippines.
- August 20 – The Gornergrat railway opens, connecting Zermatt to the Gornergrat in Switzerland.
- August 21 – Clube de Regatas Vasco da Gama is founded in Rio de Janeiro, Brazil.
- August 23 – The Southern Cross Expedition, the first British venture of the Heroic Age of Antarctic Exploration, sets sail from London.
- August 24 – Chickasaw and Choctaw tribes sign the Atoka Agreement, a requirement of the Curtis Act of 1898.
- August 25 – 700 Greeks and 15 Englishmen are slaughtered by the Turks in Heraklion, Greece, leading to the establishment of the autonomous Cretan State.
- August 28 – American pharmacist Caleb Bradham names his soft drink Pepsi-Cola.
- September 2 – Battle of Omdurman: British and Egyptian troops led by Horatio Kitchener defeat Sudanese tribesmen led by Khalifa Abdullah al-Taashi, thus establishing British dominance in the Sudan.
- September 10 – Italian anarchist Luigi Lucheni assassinates Empress Elisabeth of Austria in Geneva, as an act of propaganda of the deed.
- September 18 – Fashoda Incident: A powerful flotilla of British gunboats arrives at the French-occupied fort of Fashoda on the White Nile, leading to a diplomatic stalemate, until French troops are ordered to withdraw on November 3.
- September 21
- October 15 – The Fork Union Military Academy is founded, in Fork Union, Virginia.
- October 31 – The Lutheran Church of the Redeemer, Jerusalem, is dedicated.
- November 5 – Negros Revolution: Filipinos on the island of Negros revolt against Spanish rule and establish the short-lived Republic of Negros.
- November 10 – The Wilmington insurrection of 1898, a coup d'état by the white Democratic Party of North Carolina, begins.
- November 26 – A two-day blizzard known as the Portland Gale piles snow in Boston, severely impacting the Massachusetts fishing industry and several coastal New England towns.
- December 9 – The first of the two Tsavo Man-Eaters is shot by John Henry Patterson; the second is killed 3 weeks later, after 135 railway construction workers have been killed by the lions.
- December 10 – The Treaty of Paris is signed, ending the Spanish–American War.
- December 18 – Gaston de Chasseloup-Laubat sets the first official land speed record in an automobile, averaging 63.15 km/h (39.24 mph) over 1 km (0.62 mi) in France.
- December 26 – Marie and Pierre Curie announce the discovery of an element that they name radium.
- December 29 (December 17 Old Style) – The Moscow Art Theatre production of The Seagull by Anton Chekhov opens.
- December 31 – French serial killer Joseph Vacher is executed at Bourg-en-Bresse.