Garretson, SD has a population of 1,291 and is the 13,589th largest city in the United States. The population density is 887 per sq mi which is 8103% higher than the South Dakota average and 879% higher than the national average. The median age in Garretson is 38 which is approximately 4% higher than the South Dakota average of 37. In Garretson, 62% of the population over 15 years of age are married, 100% speak English and 0% speak Spanish. 76% of Garretson residents were born in South Dakota, 23% were born out of state, 1% were born outside of the United States and 0% were foreign born.