Going back to the days of Gen. Washington’s Continental Dragoons and pre-Revolutionary War militia units such as the Philadelphia Light Horse there have always been equestrians in the U.S. Army.
They kept up this tradition for well over 170 years of taking horses into battle.
While the remaining “official” cavalry units in the military were switched to motors in the first part of WWII, it is believed the irregular horsemen of the 10th Mountain Cavalry Reconnaissance Troop, 10th Mountain Div carried out the last cavalry charge in the Army when they rushed a German position in April 1945.
However, that was not the end of Uncle’s horses.
The Marines still train for pack horse use in Mountain Warfare School. Several Army posts in the Western States (Bliss/Huachuca/Carson) have had or currently maintain ceremonial Horse Cavalry Detachments. The Caisson Platoon endures with he Old Guard and sadly is one of the most heavily worked details in the military.
SF famously used shaggy Afghan ponies in the effort to help Dostum’s Northern Alliance in the days after 9/11 and have the monument to prove it.
Speaking of which…