Federal government

• President: William Howard Taft (R-Ohio)
• Vice President: James S. Sherman (R-New York)
• Chief Justice:

Melville Fuller (Illinois) (until July 4)

Edward Douglass White (Louisiana) (starting December 19)

• Speaker of the House of Representatives: Joseph Gurney Cannon (R-Illinois)
• Congress: 61st

January–March

• January 10–20 – The 1910 Los Angeles International Air Meet at Dominguez Field is held near Los Angeles, California (the first aviation meet to be held in the United States). ^[1]
• January 10 – Joyce Hall founds Hallmark Cards.
• January 24 – Dyer, Indiana is incorporated.
• February 8 – The Boy Scouts of America youth organization is incorporated by William D. Boyce.
• February 13 – The strike, begun on November 23, 1909, by 20,000 women against New York City's shirtwaist (blouse) factories ends after 339 manufacturers agree to a reduced workweek (52 hours a week rather than 56), increased wages and labor union recognition. ^[2]
• February 16–18 – The state of Ohio is crippled by a snowstorm.
• March 3 – Rockefeller Foundation: John D. Rockefeller Jr. announces his retirement from managing his businesses so that he can devote all his time to philanthropy.
• March 9 – The 17-month-long Westmoreland County coal strike of 1910–11, which at its peak will involve 15,000 coal miners represented by the United Mine Workers across 65 mines, begins in Westmoreland County, Pennsylvania.
• March 10 – Release of In Old California , the first film made in Hollywood, California, directed by D. W. Griffith. ^[3]
• March 12 – actress Florence Lawrence becomes "the first true movie star" after being named in advertisements, having previously been billed only as "The Biograph Girl". ^[4]
• March 14 – The Lakeview Gusher is vented into the atmosphere.
• March 19 – Republicans reduce the powers of the Speaker of the House of Representatives to influence committee membership.
• March 22 – President of the United States William H. Taft gives an American endorsement in favor of creating a "World Court" for the resolution of disputes between nations. ^[5]
• March 30 – The Mississippi Legislature founds The University of Southern Mississippi.

April–June

• April 6 – Wildwood Crest, New Jersey is incorporated as a borough of Cape May County, New Jersey.
• May 11 – The U.S. Congress establishes Glacier National Park in Montana.
• May 12 – The second National Association for the Advancement of Colored People meeting is held in New York City.
• May 16 – The U.S. Congress authorizes the creation of the United States Bureau of Mines.
• June 18 – To much fanfare, former president Theodore Roosevelt returns to New York City from a year-long African safari and tour of Europe.
• June 19 – The first unofficial Father's Day is observed.
• June 25
  • The Mann Act, known popularly as the "White Slave Traffic Act", is passed by the U.S. Congress, prohibiting the transportation of women across state lines for "immoral purposes". ^[6]
  • The U.S. Parole Commission is created, making it possible for the first time for persons convicted of a federal crime to be paroled before the end of their sentences. Prior to this, a federal prisoner could only secure an early release by commutation or pardon by the president of the U.S. ^[7]
  • The United States Postal Savings System is created by law, adapting, for the U.S. a system that had been used in European nations for people to deposit up to $2,500 into an interest-bearing (2%) account at their local post office. The system will continue in some form until 1985. ^[6]
  • The Pickett Act becomes law, giving the president of the U.S. authority to withdraw government-owned land from public use, as necessary, for government projects. ^[8]
  • The "direct system" of public land surveying begins in the U.S., replacing the system of contracting with private surveyors. ^[9]

July–September

• July 4 – African-American boxer Jack Johnson defeats white boxer James J. Jeffries in a heavyweight boxing match in Reno, Nevada, sparking race riots across the United States.
• July 22 – A wireless telegraph sent from the S.S. Montrose results in the identification and later arrest and execution of murderer Dr. Hawley Crippen.
• July 24 – James MacGillivray publishes an account of Paul Bunyan in The Detroit News .
• August 20–21 – The Great Fire of 1910 wildfire burns about 3 million acres (12,000 km²) in northeast Washington, northern Idaho, and western Montana over 2 days and kills 86 people (believed to be the largest fire in recorded United States history).

October–December

• October 1 – Los Angeles Times bombing: A bomb explodes at the Los Angeles Times building, leaving 21 dead and several injured; brothers James B. and John Joseph McNamara are later arrested and sentenced.
• October 10 – Tau Epsilon Phi fraternity is founded by ten Jewish men at Columbia University as a response to the existence of similar organizations which would not admit Jewish members.
• October 11 – Theodore Roosevelt becomes the first former president to ride in an airplane.
• November – John Lomax's pioneering collection Cowboy Songs and Other Frontier Ballads is published by Sturgis and Walton with an introduction by Theodore Roosevelt.
• November 4 – Antonio Rodríguez is burned at the stake near Rocksprings, Texas after being arrested a few days earlier for the murder of Mrs. Lem Henderson at her ranch. His murder incites race riots in both Texas and Mexico. ^[10]
• November 7 – The first air flight for the purpose of delivering commercial freight is made between Dayton and Columbus, both in Ohio, by the Wright Brothers and department store owner Max Moorehouse. Philip Parmalee is the pilot.
• November 8 – 1910 United States elections: Democrats regain control of the House of Representatives; Republicans maintain control of the Senate.
• November 17 – Ralph Johnstone, a pilot for the Wright Exhibition Team, dies at Denver, Colorado after his machine breaks apart in mid-air in full view of about 5,000 spectators. Johnstone becomes the first American pilot to die in the crash of an airplane in the United States.
• November 22 – U.S. Senator Aldrich and A. P. Andrews (Assistant Secretary of the Treasury Department), along with many of the country's leading financiers, who together represent about 1/6 of the world's wealth, are witnessed leaving Hoboken, New Jersey, on a train together. They later arrive at the Jekyll Island Club to discuss monetary policy and the banking system, an event which some say is the impetus for the creation of the Federal Reserve
• November 26 – Following the Japanese annexation of Korea in August, Japanese journalist Kioshi Kawakami publishes a propaganda article in this month's edition of World Today attempting to justify Japanese colonization of Korea. ^[11]
• December 12 – New York City socialite Dorothy Arnold disappears. Her family does not notify the police until 6 weeks later, after their own investigations fail to produce any results.
• December 19 – Edward Douglass White is sworn in as the 9th Chief Justice of the United States.
• December 31 – Two of America's premier pioneer aviators are killed on this day: John Moisant in New Orleans and Wright pilot Arch Hoxsey in Los Angeles.

Undated

• US census shows that 20.9% of the population classed as "Negro" are of mixed race.
• Henry Ford sells 10,000 cars.
• World Peace Foundation established. ^[12]

Ongoing

• Progressive Era (1890s–1920s)
• Lochner era (c. 1897–c. 1937)