Hell for Leather
The U.S. Army after its horse-cavalry peak in 1865 under Phil Sheridan. The Union eventually fielded some 258 mounted regiments and a further 170 unattached companies in the conflict, overall an amazing 175,000 blue-coat horse soldiers.
When the smoke cleared the Army established 10 peacetime cavalry regiments. These units remained in operation well into the 1930s, even being increased in number. It wasn’t until the first part of WWII that these men put their horses out to pasture for the last time.
Okrajoe posted a couple of great videos from the 1930s. U.S. Army cavalry training films. A good way to spend your lunch break if you are curious on old school horse mounted combat.
U.S. Army training film: “The Cavalry Platoon: From Mounted to Dismounted Action”, 1933.
Tactical Deployment of the .50 Caliber Machine Gun by Cavalry, Official Training Film No. 18, U.S. War Department, 1933