  the arizona territory was an organized territory of the united states that existed between 1863 and 1912, when the state of arizona was admitted to the us. the territory was created after numerous debates about splitting the new mexico territory. during the american civil war, the united states and the confederate states had different motives for dividing the new mexico territory. each claimed a territory named arizona that was a portion of the former new mexico territory. the two arizona territories played a significant role in the western campaign of the civil war. ==history== left|thumb left|thumb left|thumb after the expansion of the new mexico territory in 1853 by the gadsden purchase, proposals for a division of the territory and the organization of a separate territory of arizona in the southern half of the territory were advanced as early as 1856. the first proposals for the arizona territory were not based on the current north-south division, but rather a division along an east-west line. the proposals arose from concerns about the ability of the territorial government in santa fe to effectively administer the newly acquired southern portions of the territory.http://home.sandiego.edu/~paulb/uscivilwar/atg.html the first proposal dates 
1863_establishments_in_the_United_States Arizona_Territory Cochise_County_conflict History_of_Arizona History_of_the_American_West New_Mexico_Territory Pre-statehood_history_of_Arizona States_and_territories_disestablished_in_1912 States_and_territories_established_in_1863 Utah_Territory