The American Civil War took place. One casualty estimate includes approximately 1,500,000 horses and mules killed. A few became celebrities in their own right: Robert E. Lee's mount "Traveller"; Phil Sheridan's mount "Rienzi" (later renamed "Winchester"); 'Stonewall' Jackson's mount "Old Sorrel". During the war the White House stables burns down.

1863 The largest cavalry battle on American soil took place at Brandy Station, Virginia and involved approximately 18,000 mounted soldiers.

1865 Native American Navajos forced onto reservation.

1867 Railroad depot for cattle shipments established at Abilene, Kansas, beginning series of Chisholm Trail cattle drives from San Antonio, Texas.

1867 United States Ninth and Tenth Cavalry 'Buffalo Soldiers', African-American units are first posted to guard travelers and settlers along the Santa Fe trail and in remote southwestern areas against attacks by native American Indians. Troops are racially segregated and commanded by white officers until WWII. 

1867 Alaska acquired by United States.

1867 First running of the Belmont Stakes (today the third jewel in Thoroughbred racing's Triple Crown) in New York.

1868 The UK Royal Dublin Society included for the first time in the program of its annual Horse Show two jumping competitions: the "high leap" and the "wide leap", both derived from the Irish passion for fox hunting.

1869 Transcontinental railroad completed.

1871 The main rail terminus for cattle shipments moved from Abilene, Kansas to Dodge City, Kansas, 150 miles southwest.

1872 Photographer Eadweard Muybridge takes the first high-speed photograph. He captures an image of the celebrated racing trotter Occident, owned by Leland Stanford, completely airborne during the trot with none of his hooves touching the ground. 

1873 The American Stud Book of Thoroughbreds first published, later to become The Jockey Club.

1873 First running of the Preakness Stakes (today the second jewel in Thoroughbred racing's Triple Crown) in Baltimore, Maryland.

1874 The American Society for the Prevention of Cruelty to Animals formed in New York City in reaction to abuse of city work horses.

1874 Native Americans of central plains said to own 160,000 horses total. Cochise (Apache Nation resistance leader) dies.

1874 Barbed wire invented, plains rapidly fenced off.

1875 First running of the Kentucky Derby (today the first jewel in Thoroughbred racing's Triple Crown) in Louisville, Kentucky; won by "Aristides".

1876 George Custer and ~250 soldiers killed at Little Big Horn, Montana. Only survivor is horse 'Comanche'.

1877 Crazy Horse, leader of Oglala Sioux, captured, dies in alleged escape attempt.

1877 Chief Joseph and Nez Perce nation, using Appaloosa horses, evade five US Army units in 1350-mile dash to Canadian border, but are eventually caught in Montana.

1880s Photographers, newspaper reporters, novelists, and artists document the rapidly disappearing native American plains culture, which eventually becomes the stereotyped image of the generic "Indian".

1882 Buffalo Bill's Wild West shows launch rodeos and further develop many stereotypical images of the western United States.

1885 Last year of the eighteen years of the great cattle drives.

1885 Horse-drawn streetcars in US cities have over 6000 miles of track and carry over 188 million passengers per year (average 12 rides per year per local resident), far in advance of all other nations.

1885 Electric (horseless) trolley introduced in Baltimore, Maryland by Leo Daft.

1886 Geronimo, Apache nation leader, captured and imprisoned; dies in 1909 at Fort Sill, Oklahoma.

1886-1887 Extremely harsh winter devastates cattle ranching and ends Texas to Missouri cattle drives.

1889 Harness racing record for trotting one mile lowered to 2:12 by "Axtell" in Terre Haute, Indiana.

1889 Bison population on great plains drops to fewer than 1000 animals.

1889 Oklahoma 'land rush' of white settlers signals the end of the western frontier.

1890 Sitting Bull (Sioux nation leader) killed while allegedly resisting arrest.

1890 Wounded Knee, South Dakota killing of over 200 Oglala Sioux by the Seventh United States Cavalry effectively ends native American resistance.

1890s Most western US cavalry forts closed after cessation of 'Indian threat'.

1891 American Saddlebred Horse Association founded.

1891 American Hackney Horse Society founded.

1894 Morgan Horse Registry founded in Vermont by Colonel Joseph Battell.