1st Cavalry Regiment (1855) was a unit of the United States Army, and was the first US Army unit to be designated "Cavalry". Previously, mounted riflemen were called "Dragoons". In 1833 the "First Regiment of Dragoons" was formed and soon after that the "Second Regiment of Dragoons". These two regiments continued until 1860, when they were renamed the 1st Cavalry Regiment and the 2nd Cavalry Regiment. At the same time the 1st and 2nd Cavalry Regiments that were formed in 1855 were renamed the 4th Cavalry Regiment and the 5th Cavalry Regiment.