<Tr> <Td> </Td> <Td> Arizona Territory established </Td> <Td> February 24, 1863 </Td> </Tr> <Tr> <Td> </Td> <Td> Statehood </Td> <Td> January 6, 1912 </Td> </Tr> <P> 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 . </P> <P> In 1846, during the Mexican--American War, the U.S. provisional government of New Mexico was established . Territorial boundaries were somewhat ambiguous . After the Mexican Republic formally ceded the region to the United States in 1848, this temporary wartime / military government persisted until September 9, 1850 . </P>

When did new mexico become part of the us