The American Civil War took place between the years of 1861 and 1865, and it pitted twenty states known as the Union against eleven seceding states known as the Confederate States of America, or Confederacy. Those eleventh states were South Carolina, Mississippi, Florida, Alabama, Georgia, Louisiana, Virginia, Arkansas, Tennessee, North Carolina and Texas. Texas in particular had many infantry, cavalry and artillery units. One of those cavalry units was the 37th cavalry, also known as Terrel's Cavalry Battalion, which saw plenty of action, not in Texas though, where there weren't many battles. However, Texas did hold a strategic position in the war, and it was called the back door of the Confederacy.
Texas declared secession from the United States the first of February of 1861, and joined the Confederacy a month and a day later. In addition to being the Confederacy's back door, Texas was a supply state, providing soldiers to the Confederate army. So while there was not a lot of fighting done in Texas, scores of Texans did engage in action. As a matter of fact, more than 70,000 Texans (distributed among 45 regiments of cavalry, 23 regiments of infantry, 12 battalions of cavalry, four battalions of infantry, five regiments of heavy artillery and 30 batteries of light artillery) served in the Confederate army, and Texas regiments participated in every major battle during the war, including veterans of the Mexican-American War, and others that took part in the Texas Revolution. Moreover, Texas kept five regiments and four battalions of cavalry, and four regiments and one battalion of infantry for home defense.
Texas usefulness as a supply state ended in 1863, when the Union managed to capture the Mississippi River, making large movements of soldiers, horses and cattle impossible. Of the battles that did take place in Texas, the most important was the Second Battle of Sabine Pass, on September 8th, 1863. On that day, the US Navy Captain entered the Sabine River with four gunboats, and was joined by 18 troop transports containing 5,000 infantrymen. Stakes had been previously placed in the river to serve as markers for cannon fire. As the Union convoy entered among the stakes, Confederate soldiers opened fire with lethal precision and heavily damaged the vessels. The Union Army was forced to escape down the river after having suffered the loss of two gunboats and the capture of 200 sailors.
The most famous Texan units are probably Terry's Texas Rangers and The Texas Brigade, but Terrel's Cavalry Battalion does not fall too far behind. Terrell's Cavalry Regiment was formed in June, 1863, with Terrell's Texas Cavalry Battalion as its core. The unit fought in several locations in Louisiana. In January, 1864, it contained 25 officers and 402 men that saw action at Mansfield, and participated in the operations against the Federal Red River Campaign. It was also active at Lecompte and Yellow Bayou. The regiment disbanded in May, 1865 at Hempstead, Texas. Field officer Colonel Alexander W. Terrell was accompanied by Lieutenant Colonel John C. Robertson and Majors George W. Owens and Hiram S. Morgan.