Phoenix and Tucson Growing Together

Phoenix and Tucson are heading for a collision.

Arizona's two largest metropolitan areas are on course to meet and merge within a decade, engulfing several small towns along the way.

The downtowns of the two major cities are separated by 120 miles. But their suburbs reach much farther along Interstate 10. Planned developments stretch 60 miles south of metropolitan Phoenix, deep into Pinal County. In Tucson, new projects are heading 40 miles north into Pinal, the only county that separates the two regions. That leaves only a 20-mile gap between the two cities' growth. advertisement

Urban researchers are calling the corridor a megapolitan, or "super-sized" metropolitan area, and see it spanning from Prescott in the north all the way south to Sierra Vista and the Mexico border. The Phoenix-Tucson stretch is the epicenter.

Dubbed the Arizona Sun Corridor by researchers, the megapolitan area is one of 10 expected to be the center of most of the nation's growth during the next 35 years. The combined population of metropolitan Phoenix and Tucson today is about 5 million. Forecasts call for the swath's population to top 10 million by 2040.

"Megapolitans are the future of the country's growth," said Marshall Vest, an economist and director with the Economic and Business Research Center at the University of Arizona's Eller College of Management in Tucson. "Phoenix and Tucson are already merging into one, but the growth is much more than just a corridor of land filling in."

Being part of a megapolitan designates an area as a growth magnet. Government is starting to look at the areas as places for better planning. That, along with projections for growth, can mean more federal money for projects such as freeways.

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