Conversation so far:
what is the population of the state of arizona
The most recent population estimates released by the US Census put Arizona's population at 6,828,065 in 2015.
is the population of Arizona growing
New population figures for the year ending July 1, 2006, indicate that Arizona is the fastest growing state in the United States, with 3.6% population growth since 2005.
where is the majority of people located in Arizona
The center of population of Arizona is located in Maricopa County, which contains over 61% of Arizona's population.

Question: what cities are in the county
Self-contained rewrite: what cities are in Arizona's Maricopa County