Dragoon info from KC Steve, the best Dragoon campsite finder and hunter I know....
Important fact, in the mid nineteenth century just prior to the Civil War, three different types of mounted troops existed simultaneously in the United States Army: cavalry, dragoons, and mounted riflemen. While all traveled on horseback, theoretically, there were enough distinctions between the various units to merit them being called by different names.
The United States Army back in 1844 consisted of 8573 men of which ten companies of First Dragoons numbered about 623 men.
Each company at full strength had a captain, a first lieutenant, a second lieutenant, four sergeants, four corporals, two buglers, one farrier and blacksmith, and fifty privates. The men were armed with Hall's carbines and, later, musketoons, Dragoon sabers called “old wristbreakers” of the Prussian pattern, and horse pistols.
Besides dragoons, there were also mounted riflemen stationed at Fort Scott.
The United States Army organized a regiment of mounted riflemen in 1845, for defense of forts along the Oregon Trail. This regiment fought in the Mexican War and then was later assigned to duties in the far West. Two companies of mounted riflemen were stationed at Fort Scott from 1852-53, but by that time Fort Scott was obsolete. The army abandoned Fort Scott in 1853.
The difference between mounted riflemen and dragoons was in their weaponry. Dragoons were armed with carbines, sabers, and pistols. Mounted riflemen had no sabers and had, as the name implied-rifles. Cavalry were armed with sabers.
The U.S. Army organized two cavalry regiments in 1855, so by the late 1850's, the army had two regiments of dragoons, one regiment of mounted riflemen, and two regiments of light cavalry. To simplify matters, in 1861, all of the mounted regiments were redesignated or renamed cavalry.
The differences? Cavalry is more of a reconnaissance or a screening force. The cavalry were supposed to be the eyes and ears of the army. Commanding generals relied on cavalry to know the enemy's troop strength and movements. Cavalry did most of their fighting on horseback. Dragoons on the other hand, did most of their fighting dismounted. The horses provided them with mobility but for the most part they dismounted when they went into action, using their carbines or musketoons. However, they were armed with sabers and thus were trained to fight both mounted and dismounted.