Castor, LA has a population of 275 and is the 22,916th largest city in the United States. The population density is 231 per sq mi which is 160% higher than the Louisiana average and 155% higher than the national average. The median age in Castor is 28 which is approximately 24% lower than the Louisiana average of 36. In Castor, 72% of the population over 15 years of age are married, 98% speak English and 2% speak Spanish. 80% of Castor residents were born in Louisiana, 19% were born out of state, 0% were born outside of the United States and 1% were foreign born.