South Hills, MT has a population of 529 and is the 19,201st largest city in the United States. The population density is 90 per sq mi which is 1218% higher than the Montana average and 1% lower than the national average. The median age in South Hills is 31 which is approximately 23% lower than the Montana average of 40. In South Hills, 74% of the population over 15 years of age are married, 98% speak English and 0% speak Spanish. 55% of South Hills residents were born in Montana, 42% were born out of state, 2% were born outside of the United States and 1% were foreign born.