New Mexico Territory

territory of the United States of America, 1850-1912

The Territory of New Mexico was an organized incorporated territory of the United States that existed (with varying boundaries) from September 9, 1850, until January 6, 1912, when the remaining extent of the territory was admitted to the Union as the State of New Mexico, making it the longest-lived organized incorporated territory of the United States, lasting approximately 62 years.

Territory of New Mexico
Organized incorporated territory of the United States





Flag Coat of arms
Flag Coat of arms
Location of New Mexico Territory
A map of the later Federal Arizona and New Mexico Territories, split from the original New Mexico Territory of 1851, showing existing counties.
Capital Santa Fe
Government Organized incorporated territory
 •  1851–1852 James S. Calhoun
 •  1910–1912 William J. Mills
Legislature New Mexico Territorial Legislature
 •  Treaty of Guadalupe Hidalgo May 30, 1848
 •  Organic Act (part of Compromise of 1850) September 9, 1850
 •  Gadsden Purchase June 24, 1853
 •  Colorado Territory established February 28, 1861
 •  Arizona Territory established February 24, 1863
 •  Statehood January 6, 1912


  • David L. Caffey, Chasing the Santa Fe Ring: Power and Privilege in Territorial New Mexico. Albuquerque, NM: University of New Mexico Press, 2014.