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".[2]
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.[3]
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.[2][4]
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.[5]
The "direct system" of public land surveying begins in the U.S., replacing the system of contracting with private surveyors.[6]
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.
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 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.
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.[7]
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 Japanese annexation of Korea in August, Japanese journalist Kioshi Kawakami publishes propaganda article in November edition of "World Today" attempting to justify Japanese colonization of Korea.[8]
December 12 – New York CitysocialiteDorothy Arnold disappears. Her family does not notify the police until 6 weeks later, after their own investigations fail to produce any results.
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.