Greenbriar, FL has a population of 2,764 and is the 9,214th largest city in the United States. The population density is 4,629 per sq mi which is 1477% higher than the Florida average and 5009% higher than the national average. The median age in Greenbriar is 46 which is approximately 11% higher than the Florida average of 42. In Greenbriar, 52% of the population over 15 years of age are married, 79% speak English and 11% speak Spanish. 30% of Greenbriar residents were born in Florida, 55% were born out of state, 3% were born outside of the United States and 13% were foreign born.