The Battle of Glorieta Pass was fought March 26–28, 1862 in the northern New Mexico Territory, by Union and Confederate forces during the American Civil War. While not the largest battle of the New Mexico campaign, the Battle of Glorieta Pass ended the Confederacy's efforts to capture the territory and other parts of the western United States.

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.