Fort Defiance, AZ has a population of 4,022 and is the 7,428th largest city in the United States. The population density is 661 per sq mi which is 1050% higher than the Arizona average and 630% higher than the national average. The median age in Fort Defiance is 34 which is approximately 8% lower than the Arizona average of 37. In Fort Defiance, 30% of the population over 15 years of age are married, 52% speak English and 0% speak Spanish. 83% of Fort Defiance residents were born in Arizona, 17% were born out of state, 0% were born outside of the United States and 0% were foreign born.