Casa Grande, AZ has a population of 51,571 and is the 789th largest city in the United States. The population density is 468 per sq mi which is 713% higher than the Arizona average and 416% higher than the national average. The median age in Casa Grande is 36 which is approximately 3% lower than the Arizona average of 37. In Casa Grande, 55% of the population over 15 years of age are married, 76% speak English and 20% speak Spanish. 45% of Casa Grande residents were born in Arizona, 44% were born out of state, 2% were born outside of the United States and 10% were foreign born.