Gadsden Purchase
The state, like its neighbors in the Southwest, has had close linguistic and cultural ties with Mexico. The state, except for the 1853 Gadsden Purchase, was part of the New Mexico Territory until 1863, when the western half was made into Arizona Territory. The area of the former Gadsden Purchase spoke mostly Spanish until the 1940s although the Tucson area had a higher ratio of anglophones (including Mexican Americans who were fluent in English). The continuous arrival of Mexican settlers increases the number of Spanish-speakers.