Diablo Grande, CA has a population of 1,079 and is the 14,670th largest city in the United States. The population density is 211 per sq mi which is 9% lower than the California average and 133% higher than the national average. The median age in Diablo Grande is 37 which is approximately 3% higher than the California average of 36. In Diablo Grande, 65% of the population over 15 years of age are married, 73% speak English and 21% speak Spanish. 58% of Diablo Grande residents were born in California, 20% were born out of state, 2% were born outside of the United States and 20% were foreign born.