Custer, SD has a population of 1,770 and is the 11,744th largest city in the United States. The population density is 772 per sq mi which is 7043% higher than the South Dakota average and 752% higher than the national average. The median age in Custer is 54 which is approximately 45% higher than the South Dakota average of 37. In Custer, 61% of the population over 15 years of age are married, 99% speak English and 0% speak Spanish. 55% of Custer residents were born in South Dakota, 45% were born out of state, 0% were born outside of the United States and 0% were foreign born.