The city of Tucson, located in Pima County, Arizona, USA is about 200 kilometers - or 120 miles - southeast of Phoenix, Arizona.
The 2005 census puts the population of Tucson at about 500,000 citizens, where the metropolitan population is nearly one million citizens. Estimated population growth by 2008 will put the population just over 600,000 - currently it stands at the 32nd largest city in the United States, and the largest city in southern Arizona (second largest in the whole state, second to, of course, Phoenix, Arizona).
Tucson is divided in to the suburbs of Oro Valley, Marana, South Tucosn, and Sahuarita. An alternate method of dividing gives you communities of Tucson, which include Casas Adobes, Catalina, Catalina Foothills, Green Valley, Flowing Wells, Tanque Verde, and Vail.
Tucson has a fairly consistant growth, and has through recent history remained rather steady, this makes Tucson a rather safe real estate market to invest in, likely the most safe of the entire state of Arizona. Though, it would be worth doing detailed research in to the market before making commitment.