Williamson, AZ has a population of 5,207 and is the 6,280th largest city in the United States. The population density is 92 per sq mi which is 59% higher than the Arizona average and 1% higher than the national average. The median age in Williamson is 63 which is approximately 70% higher than the Arizona average of 37. In Williamson, 80% of the population over 15 years of age are married, 97% speak English and 1% speak Spanish. 14% of Williamson residents were born in Arizona, 80% were born out of state, 1% were born outside of the United States and 5% were foreign born.