The Territory of New Mexico was an organized incorporated territory of the United States from September 9, 1850, until January 6, 1912. It was created from the U.S. provisional government of New Mexico, as a result of Nuevo México becoming part of the American frontier after the Treaty of Guadalupe Hidalgo. It existed with varying boundaries until the territory was admitted to the Union as the U.S. state of New Mexico. This jurisdiction was an organized, incorporated territory of the US for nearly 62 years, the longest period of any territory in the contiguous United States.
Arizona Territory, colloquially referred to as Confederate Arizona, was an organized incorporated territory of the Confederate States of America that existed from August 1, 1861, to May 26, 1865, when the Confederate States Army Trans-Mississippi Department, commanded by General Edmund Kirby Smith, surrendered at Shreveport, Louisiana. However, after the Battle of Glorieta Pass, the Confederates had to retreat from the territory, and by July 1862, effective Confederate control of the territory had ended. Delegates to the secession convention had voted in March 1861 to secede from the New Mexico Territory and the Union, and seek to join the Confederacy. It consisted of the portion of the New Mexico Territory south of the 34th parallel, including parts of the modern states of New Mexico and Arizona. The capital was Mesilla, along the southern border. The breakaway region overlapped Arizona Territory, established by the Union government in February 1863.
The New Mexico campaign was a military operation of the trans-Mississippi theater of the American Civil War from February to April 1862 in which Confederate Brigadier General Henry Hopkins Sibley invaded the northern New Mexico Territory in an attempt to gain control of the Southwest, including the gold fields of Colorado and the ports of California. Historians regard this campaign as the most ambitious Confederate attempt to establish control of the American West and to open an additional theater in the war. It was an important campaign in the war's Trans-Mississippi Theater, and one of the major events in the history of the New Mexico Territory in the American Civil War.
The Battle of Picacho Pass, also known as the Battle of Picacho Peak, was an engagement of the American Civil War on April 15, 1862. The action occurred around Picacho Peak, 50 miles (80 km) northwest of Tucson, Arizona. It was fought between a Union cavalry patrol from California and a party of Confederate pickets from Tucson, and marks the westernmost battle of the American Civil War involving fatalities.
The First Battle of Mesilla was fought on July 25, 1861, at Mesilla in New Mexico Territory, in present-day Doña Ana County, New Mexico.
The Battle of Peralta was a minor engagement near the end of Confederate General Henry Hopkins Sibley's 1862 New Mexico Campaign.
The Army of New Mexico, also known as the Sibley Brigade, was a small Confederate field army in the American Civil War. It operated in Confederate Arizona and New Mexico Territory during the New Mexico Campaign in late 1861 and early 1862, before it was transferred to Louisiana. At first the force was tasked with securing Confederate Arizona's forts, most of which were still in Union hands. John R. Baylor had already established the Confederate Territory of Arizona after the First Battle of Mesilla in 1861. Now the goal was to capture the remaining U.S. held forts in Confederate Arizona and to invade New Mexico Territory. The army also hoped to capture the mines of Colorado and California, to secure gold and silver supplies to finance the Confederate war effort. Ultimately, the Confederate plans were thwarted at the Battle of Glorieta Pass.
Fort Fillmore, located at 32°13′30″N 106°42′52″W, was a United States military fortification established by Colonel Edwin Vose Sumner in September 1851 near Mesilla in what is now New Mexico, primarily for the purpose of protecting settlers and traders traveling to California. Early frontier migrants were under constant threat from attack by local Native Americans, and a network of forts was eventually created by the U.S. government to protect and encourage westward expansion. Fort Fillmore was intended to protect a corridor plagued by hostile Apaches, where several migration routes converged between El Paso and Tucson to take advantage of Apache Pass.
The trans-Mississippi theater of the American Civil War was the scene of the major military operations west of the Mississippi River. The area is often thought of as excluding the states and territories bordering the Pacific Ocean, which formed the Pacific coast theater of the American Civil War (1861–1865).
The California Column was a force of Union volunteers sent to Arizona and New Mexico during the American Civil War. The command marched over 900 miles (1,400 km) from California through Arizona and New Mexico Territory to the Rio Grande and as far east as El Paso, Texas, between April and August 1862.
The New Mexico Territory, comprising what are today the U.S. states of New Mexico and Arizona, as well as the southern portion of Nevada, played a small but significant role in the trans-Mississippi theater of the American Civil War. Despite its remoteness from the major battlefields of the east, and its being part of the sparsely populated and largely undeveloped American frontier, both Confederate and Union governments claimed ownership over the territory, and several important battles and military operations took place in the region. Roughly 7,000-8,000 troops from the New Mexico Territory served the Union, more than any other western state or territory.
The First Battle of Dragoon Springs was a minor skirmish between a small troop of Confederate dragoons of Governor John R. Baylor's Arizona Rangers, and a band of Apache warriors during the American Civil War. It was fought on May 5, 1862, near the present-day town of Benson, Arizona, in Confederate Arizona.
Prior to the adoption of its name for a U.S. state, Arizona was traditionally defined as the region south of the Gila River to the present-day Mexican border, and between the Colorado River and the Rio Grande. It encompasses present-day Southern Arizona and the New Mexico Bootheel plus adjacent parts of Southwestern New Mexico. This area was transferred from Mexico to the United States in the Gadsden Purchase of 1853. Mining and ranching were the primary occupations of traditional Arizona's inhabitants, though growing citrus fruits had long been occurring in Tucson.
The Battle of Canada Alamosa as it was known to the Union Army, or Alamosa as it was known to the Confederates, was a skirmish of the American Civil War on the late evening of September 24 and the morning of September 25, 1861. It was one of several small battles that occurred in Confederate Arizona near the border with Union held New Mexico Territory, this one being the largest.
The Company A, Arizona Rangers was a cavalry formation of the Confederate States Army during the American Civil War.
The Department of New Mexico was a department of the United States Army during the mid-19th century. It was created as the 9th Department, a geographical department, in 1848 following the successful conclusion of the Mexican–American War, and renamed Department of New Mexico in 1853. It had to contend with an invading Confederate force during the New Mexico Campaign of the American Civil War from mid-1861 to early 1862, then with Apache tribes during the remainder of the conflict. It was merged into the Department of California after the end of the war as the District of New Mexico.
Union forces entered Tucson on May 20, 1862, with a force of 2,000 men without firing a shot.
Fort Thorn or Fort Thorne, originally Cantonment Garland, was a settlement and military outpost located on the west bank of the Rio Grande, northwest of present-day Hatch, and west of Salem in Doña Ana County, New Mexico, United States. It was named for 1st Lt. Herman Thorn of the 2nd U.S. Infantry drowned in the Colorado River in 1849. He had previously been an aide to General John Garland, the new commander of the Ninth Military District, that encompassed New Mexico Territory in 1853.
The Butterfield Overland Mail was a transport and mail delivery system that employed stagecoaches that travelled on a specific route between St. Louis, Missouri and San Francisco, California and which passed through the New Mexico Territory. It was created by the United States Congress on March 3, 1857, and operated until March 30, 1861. The route that was operated extended from where the ferry across the Colorado River to Fort Yuma Station, California was located, through New Mexico Territory via Tucson to the Rio Grande and Mesilla, New Mexico then south to Franklin, Texas, midpoint on the route. The New Mexico Territory mail route was divided into two divisions each under a superintendent. Tucson was the headquarters of the 3rd Division of the Butterfield Overland Mail Company. Franklin Station in the town of Franklin,, was the headquarters of the 4th Division.
Sherod Hunter was the commander of the Confederate unit operating against Union Army forces in present-day Arizona during the American Civil War. He later commanded various Confederate cavalry units elsewhere in the Trans-Mississippi Theater.
Confederate States 
United States 
