President: Andrew Johnson (D-Tennessee)
Vice President: vacant
Chief Justice: Salmon P. Chase (Ohio)
Speaker of the House of Representatives: Schuyler Colfax (R-Indiana)
January 6 – Asa Mercer and a number of new "Mercer Girls" sail from Massachusetts for the West Coast, arriving in Seattle on May 23.
January 9 – John William De Forest, writing for The Nation, calls for a more specifically American literature; the essay's title, "The Great American Novel", is the first known use of the term.
February 16 – In New York City the Jolly Corks organization is renamed the Benevolent and Protective Order of Elks (BPOE).
Impeachment of Andrew Johnson: Three days after his action to dismiss Secretary of War Edwin M. Stanton, the House of Representatives votes 126 to 47 in favor of a resolution to impeach Andrew Johnson, the first of two Presidents to be impeached by the full House. Johnson is later acquitted by the Senate.
The first parade to have floats occurs at Mardi Gras in New Orleans, Louisiana.
March 1 – The Pi Kappa Alpha Fraternity is founded at the University of Virginia.
March 5 – A court of impeachment is organized in the United States Senate to hear charges against President Andrew Johnson.
March 23 – The University of California is founded in Oakland, California, when the Organic Act is signed into California law.
March 27 – The Lake Ontario Shore Railroad Company is organized in Oswego, New York.
April 1 – The Hampton Normal and Agricultural Institute is established in Hampton, Virginia.
April 29 – After pursuing a policy of total war on the Plain Indians, General William Tecumseh Sherman brokers the Treaty of Fort Laramie (1868).
May 16 and 26 – President Andrew Johnson is acquitted during his impeachment trial, by one vote in the United States Senate.
May 30 – Memorial Day is observed in the United States for the first time (it was proclaimed on May 5 by General John A. Logan).
July 25 – Wyoming Territory is organized.
July 28 – The 14th Amendment to the United States Constitution is adopted, guaranteeing African Americans full citizenship and all persons in the United States due process of law.
September – The first volume of Louisa May Alcott's novel Little Women is published.
September 18 – The University of the South holds its first convocation in Sewanee, Tennessee.
September 23 – Rebels (some 400–600) in the town of Lares declare Puerto Rico independent; the local militia easily defeats them a week later.
October 6 – The City of New York grants Mount Sinai Hospital a 99-year lease for a property on Lexington Avenue and 66th Street, for the sum of $1.00.
October 28 – Thomas Edison applies for his first patent, the electric vote recorder.
November 3 – U.S. presidential election, 1868: Ulysses S. Grant defeats Horatio Seymour in the election.
November 27 – Indian Wars – Battle of Washita River: In the early morning, United States Army Lieutenant Colonel George Armstrong Custer leads an attack on a band of Cheyenne living on reservation land with Chief Black Kettle, killing 103 Cheyenne.
December 25 – President Andrew Johnson grants unconditional pardon to all Civil War rebels.
Maryland School for the Deaf is established.
The Roman Catholic See of Tucson is established as the Apostolic Vicariate of Arizona in 1868, taking its territory from the former Diocese of Santa Fe. The Diocese of Tucson is canonically erected on May 8, 1897.
Reconstruction era (1865–1877)
Early ? (or November 24?) – Scott Joplin, African American ragtime composer and pianist (died 1917)
January 31 – Theodore William Richards, chemist, recipient of Nobel Prize in Chemistry in 1914 (died 1928)
February 3 – William J. Harris, U.S. Senator from Georgia from 1919 till 1932 (died 1932)
February 5 – Maxine Elliott, actress and businesswoman (died 1940 in France)
February 10 – William Allen White, journalist (died 1944)
February 20 – John Nathan Cobb, author, naturalist, conservationist, fisheries researcher and educator (died 1930)
February 23 – W. E. B. Du Bois, African American civil rights leader (died 1963)
April 6 – Helen Hyde, etcher and engraver (died 1919)
April 8 – Herbert Jennings, zoologist (died 1947)
April 12 – Ella Gaunt Smith, doll-maker (died 1932)
April 21 – Alfred Henry Maurer, modernist painter (suicide 1932)
March 22 – Robert Millikan, physicist, recipient of Nobel Prize in Physics in 1923 (died 1953)
May 2 – Robert W. Wood, optical physicist (died 1955)
May 10 – Ed Barrow, baseball player and manager (died 1953)
June 4 – Thomas F. Bayard, Jr., U.S. Senator from Delaware from 1922 to 1929 (died 1942)
June 8 – Robert Robinson Taylor, first accredited African American architect (died 1942)
June 28 – John F. Nugent, U.S. Senator from Idaho from 1918 to 1921 (died 1931)
July 4 – Henrietta Swan Leavitt, astronomer (died 1921)
August 21 – Vess Ossman, ragtime banjo player
August 23 – Edgar Lee Masters, poet, biographer, dramatist and lawyer (died 1950)
September 8 – Seth Weeks, African American jazz mandolin player, composer, arranger and bandleader (died 1953)
September 9 – Mary Hunter Austin, writer (died 1934)
September 11 – Henry Justin Allen, U.S. Senator from Kansas from 1929 to 1931 (died 1950)
September 22 – John T. Raulston, state judge (died 1956)
October 8 – Coleman Livingston Blease, U.S. Senator from South Carolina from 1925 to 1931 (died 1942)
November 22 – John Nance Garner, 32nd Vice President of the United States from 1933 to 1941 (died 1967)
November 23 – Mary Brewster Hazelton, portrait painter (died 1953)
December 17 – Frederic M. Sackett, U.S. Senator from Kentucky from 1925 to 1930 (died 1941)
December 19 – Eleanor H. Porter, novelist (died 1920)
December 25 – Eugenie Besserer, silent film actress (died 1934)
Richard H. Bayard, U.S. Senator from Delaware from 1841 to 1845 (born 1796)
Jesse Chisholm, pioneer (born c. 1805)
May 10 – Henry Bennett, politician (born 1808)
May 23 – Kit Carson, trapper, scout and Indian agent (born 1809)
May 24 – Emanuel Leutze, history painter (born 1816 in Germany)
May 31 – John J. McRae, U.S. Senator from Mississippi from 1851 to 1852 (born 1815)
June 1 – James Buchanan, 15th President of the United States from 1857 to 1861 (born 1791)
June 6 – Daniel Pierce Thompson, novelist and lawyer (born 1795)
June 22 – Heber C. Kimball, Latter Day Saint leader (born 1801)
August 11 – Thaddeus Stevens, politician (born 1792)
September 19 – William Sprague, minister and politician from Michigan (born 1809)
October 9 – Howell Cobb, politician (born 1815)
November 27 – Black Kettle, Southern Cheyenne Peace Chief (born 1803)
December 25 – Linus Yale, Jr., inventor (born 1821)
1868 in the United States Wikipedia
Events from the year 1868 in the United States.