Gregory, SD has a population of 1,485 and is the 12,746th largest city in the United States. The population density is 863 per sq mi which is 7090% higher than the South Dakota average and 852% higher than the national average. The median age in Gregory is 49 which is approximately 34% higher than the South Dakota average of 37. In Gregory, 62% of the population over 15 years of age are married, 93% speak English and 2% speak Spanish. 79% of Gregory residents were born in South Dakota, 20% were born out of state, 0% were born outside of the United States and 1% were foreign born.