Arizona’s population is heavily concentrated in Maricopa County, home to nearly 4.65 million residents and growing at 5.4% since 2020. While Pima County, the second most populous with over 1 million residents, has experienced modest growth at 2.8%, the fastest growth has occurred in rapidly developing Pinal County at 21.5%. The state shows dramatic population density contrasts, from Maricopa’s 520 people per square mile to vast Coconino County, which despite being nearly twice the size of Connecticut at 18,617 square miles, has only 8 people per square mile. Three rural counties – Apache County, Cochise County, and Greenlee County – have experienced population declines since 2020.