February – The journal Science is first published, with financial backing from Thomas Edison.

February 2 – The first electric streetlight is installed in Wabash, Indiana.

March 31 – Wabash, Indiana becomes the first electrically lighted city in the world.

May 11 – Mussel Slough Tragedy: A land dispute between the Southern Pacific Railroad and settlers in Hanford, California, turns deadly when a gun battle breaks out, leaving 7 dead.

May 13 – In Menlo Park, New Jersey, Thomas Edison performs the first test of his electric railway.

May 30 – League of American Wheelmen is founded in Newport, Rhode Island.

June 1 – United States Census is 50,155,783. More than 100,000 Chinese men and 3,000 Chinese women are living in the western United States.

August 1 – Rufus W. Cobb is reelected the 25th governor of Alabama defeating James Madison Pickens.

September 30 – Amateur astronomer Henry Draper takes the first ever photograph of the Orion Nebula.

October 6 – The University of Southern California opens its doors to 53 students and 10 faculty.

October 15 – The first blizzard mentioned in Laura Ingalls Wilder's The Long Winter sweeps over the prairie in Dakota Territory.

November 2 – U.S. presidential election, 1880: James Garfield defeats Winfield S. Hancock.

November 4 – The first cash register is patented by James and John Ritty of Dayton, Ohio.

November 22 – Vaudeville actress Lillian Russell makes her debut at Tony Pastor's Theatre in New York City.

George Alford is sentenced to five years imprisonment for murdering a sheriff in Fort Worth, Texas.

Mar 2 James Allen kills James Moorehead after ordering eggs in a tavern in Las Vegas, New Mexico and, after escaping from prison for Moorehead's murder, is killed by a posse.

Apr 15 The first widely popular incarnation of the Farmers' Alliance, an agrarian reform movement, is founded in Chicago by George Milton through his periodical Western Rural and quickly builds a membership across the Midwest and Plains.

May 1 The Tombstone Epitaph prints its first issue in Tombstone, Arizona. It remains the oldest continuously published newspaper in the state.

May 11 A dispute over land titles between settlers of California's San Joaquin Valley and the Southern Pacific Railroad leaves seven people dead in what is later called the Mussel Slough Tragedy.

Oct 30 Marshal Fred White dies in Tombstone, Arizona after being accidentally shot in the groin two days earlier, attempting to disarm 'Curly' Bill Brocius.

Dec 19 Tom O'Folliard, best friend of Billy the Kid, is shot and killed by members of Pat Garrett's posse in Fort Sumner, New Mexico.

Dec 23 Charlie Bowdre, a member of Billy the Kid's gang, is shot and killed by members of Pat Garrett's posse at Stinking Springs, New Mexico.