The 1st Cavalry Regiment is a United States Army regiment that has its antecedents in the early 19th century in the formation of the United States Regiment of Dragoons. To this day, the unit's special designation is "First Regiment of Dragoons". While they were the First Regiment of Dragoons another unit designated the 1st Cavalry Regiment was formed in 1855 and in 1861 was re-designated as the 4th Cavalry Regiment (units were renumbered based on seniority and it was the fourth oldest mounted regiment in active service). The First Dragoons became the 1st Cavalry Regiment since they were the oldest mounted regiment.