Southern Arizona

Southern Arizonais a region of theUnited Statescomprising the southernmost portion of theState of Arizona.It sometimes goes by the nameGadsdenorBaja Arizona,which means "Lower Arizona" in Spanish.

Southern Arizona is the area of Arizona south of the Gila River, roughly corresponding to the area from the 1854 Gadsden Purchase (shown on the map in yellow with present-day state boundaries and cities)

Geography

The Gila River is generally considered the northern boundary of southern Arizona

Although Southern Arizona's boundaries are not well-defined, it is generally considered to include all areas south of theGila Riverbut sometimes onlyCochise County,Pima CountyandSanta Cruz County,anchored by the city ofTucson.Other cities and large towns in Southern Arizona includeAjo,Casa Grande,Gila Bend,Oro Valley,Sierra Vista,Yuma,and the border cities ofNogalesandDouglas.

Furthermore, the populated areas of Southern Arizona include the majorU.S. Armypost ofFort HuachucaandDavis–Monthan Air Force Baseof theU.S. Air Force.

The most major scientific site of Southern Arizona is the set of severalastronomical observatoriesof theKitt Peak National Observatory,a reasonable distance west-southwest of Tucson.

Southern Arizona is the location of several largenational monumentsprotecting the scenery, wildlife, andarchaeological sitesof Southern Arizona, and theSaguaro National Park,which stands on two large sections of land, one west of theTucson metropolitan areaand the other one east of Tucson.

The region includes several small mountain ranges including theChiricahua Mountains,Huachuca Mountains,Santa Ritas,theSanta Catalinas,theRincons,thePiñalenos,and others. As surprising as it might seem, some of these mountains are high enough, cold enough, and wet enough in the wintertime to providealpine skiingat regular ski resorts, with ski lifts, not very distant from cities such as Tucson.

Transportation

Significant distances requiring transportation in Southern Arizona are generally traveled by highway and the railroad. Southern Arizona is the location of the major transcontinental Interstate highwayInterstate 10from the border withNew Mexicowestward through Tucson, and then continuing northwest via Casa Grande to the Phoenix–Scottsdale–Mesa metropolis. Also, running westward from Casa Grande isInterstate 8,which goes via Yuma intoCalifornia,crossing the Colorado River. Finally, the shortInterstate 19runs south from Tucson to Nogales, Arizona, and a major border crossing into Mexico. In addition, the much older Federal highway,U.S. Route 80,crosses Southern Arizona from east to west from the New Mexico border, nearly to the California border, and formerly into California to thePacific Ocean.However, its westernmost stretch has been replaced by Interstate 8, which was built on top of it and its right-of-way.

ATranscontinental Railroadcrosses Southern Arizona via Tucson and Phoenix. Also, there is a major railroad south fromNorthern Arizona,via Phoenix, Casa Grande, and Tucson, to Nogales, where it crosses the border and meets the Mexican railroads.

The primary major airport of southern Arizona, Tucson International Airport, is located just south of Tucson.

History

Stone Avenue in the year 1880 in Tucson, southern Arizona's largest city

Southern Arizona has been inhabited by human beings for several millennia. TheHohokamwere the principalPre-Columbianinhabitants of the area. In more recent times, the dominant indigenous group ofNative Americanshave been theO'odhamtribe, which continues to reside in this area in their traditional homeland.

SeveralSpanishmissions were established in the early 18th century byFather Eusebio Francisco Kinoin what was then known as thePimería Alta.After theMexican–American Warof 1846–47, much of Southern Arizona was purchased by the United States from Mexico for $15,000,000 in theGadsden Purchaseof 1854.

More recently, Southern Arizona played an important role during theCold War.Davis-Monthan AFB was the home base of anair force wingof 18 heavyTitan IIIntercontinental Ballistic Missilesdispersed over a wide area of launch sites – south, southwest, and southeast of Tucson. Due to their advancing age and the advent of several importantStrategic Nuclear Weapons Reduction treaties,all of these missiles were retired from service by the mid-1980s.All but one of their launch silos and command shelters were demolished with explosives. The remaining site, Titan II ICBM Site 571-7, about 15 miles south of Tucson onInterstate 19,serves as theTitan Missile Museum,a National Historic Landmark.

Secession

Beginning in 1987, a group of southern Arizonans have considered seceding from the rest of Arizona to form a new U.S. state, potentially named Baja Arizona or Gadsden. A political push to that effect began in February, 2011, led by a group of attorneys largely in opposition to what they perceived as anativist,conservative dominance in the Phoenix area in contrast to theDemocratsof the south. The organizers of this movement had aimed to hold a referendum vote on the matter in 2012 inPima County(and, possibly,Santa Cruz CountyandCochise County).As of 2013,no ballot initiatives had been generated.