President Andrew Jackson on 23 May 1836, as the Second Regiment of Dragoons of the US Army. A and I Companies were recruited in the Fort Myer, Virginia area, B Company recruited from Virginia and Louisiana, C Company drew recruits from Tennessee, E, F, G, and H recruited from New York, and K Company was drawn from New Orleans. D Company was organized from a detachment of the 1st Dragoons and served in Florida immediately. In April 1837, the regimental headquarters was moved to Jefferson Barracks, Missouri, where the 400 new recruits and their instructors participated in the School of the Trooper, and learned the tactics and ways of being a dragoon, while some of their compatriots were battling the Indians in Florida. Second Seminole War The 2nd Dragoons saw their first combat during the Second Seminole War. Company D drew first blood on 10 June 1836 in an engagement at Welika Pond, close to Fort Defiance, Florida. In December 1836, A, B, C, E, and I Companies arrived in South Carolina, and immediately moved south. In January 1837, the troopers were engaged by the Seminoles at Fort Mellon only two days after their arrival. On 9 September 1837, three Dragoon companies and two companies of Florida militia surrounded and attacked a hostile village, capturing King Philip, an important chief. The 2nd Dragoons brought the fight to the hostile Seminoles, rather than wait to be ambushed inside a fort like other units did. Mexican–American War Under an act of Congress dated 23 August 1842 the regiment was re-designated as the Regiment of Riflemen effective 4 March 1843. This act was repealed on 4 April 1844 and the regiment reverted to its previous designation. In October 1842, A, D, E, F, and G Companies moved to Fort Jessup, Louisiana and Fort Towson. The remainder of the regiment stayed in Florida to patrol for hostile bands of Seminoles. Fort Jessup became the regimental headquarters, and was the 2nd Dragoons' home for four years. When hostilities with the Centralist Republic of Mexico began to boil over in 1845, General Zachary Taylor assembled his "Army of Observation" at Fort Jessup, and the 2nd Dragoons marched overland to occupy Corpus Christi, Texas. They soon established Fort Texas, near modern-day Brownsville, Texas. The regiment conducted aggressive patrolling along the Rio Grande, and on 25 April 1846, they received word that Mexican troops were crossing the river.