Castleford, ID has a population of 180 and is the 24,916th largest city in the United States. The population density is 1,880 per sq mi which is 9754% higher than the Idaho average and 1975% higher than the national average. The median age in Castleford is 33 which is approximately 8% lower than the Idaho average of 36. In Castleford, 46% of the population over 15 years of age are married, 66% speak English and 34% speak Spanish. 58% of Castleford residents were born in Idaho, 28% were born out of state, 0% were born outside of the United States and 14% were foreign born.