They're all parts of larger metro areas. Scottsdale and Chandler are part of Phoenix, Hialeah is in Miami, Henderson is in Las Vegas, and Fremont is in the Bay Area.
It's interesting, Louisville and San Francisco have a similar median age, but their age distributions are very different. Louisville's is more balanced, while San Francisco has a disproportionate number of millenials and older adults and very few children in comparison.