On the east side everything from about 56th Street eastward including the East Valley Suburbs, and the Town of Paradise Valley (which goes as far west as 32nd St) became Area Code 480 as well as the city North of Union Hills and east of the 2000 E Grid.
The western suburbs and the city west of 39th Ave North of Indian School to west of 63rd Ave from I-10 south became Area code 623, along with the city from North of Union Hills and west of the 2000 E Grid.
Only two cities ended with multiple area codes with this change. Most areas of Phoenix are 602, however, some few areas have the 480 area code. Glendale, Arizona's northern half has the area code divider running diagonally through its middle. In some neighborhoods, homes only a few hundred feet away from each other may have different area codes; 602 or 623.