Montana City, MT has a population of 2,878 and is the 9,021st largest city in the United States. The population density is 84 per sq mi which is 1136% higher than the Montana average and 7% lower than the national average. The median age in Montana City is 46 which is approximately 15% higher than the Montana average of 40. In Montana City, 73% of the population over 15 years of age are married, 99% speak English and 0% speak Spanish. 57% of Montana City residents were born in Montana, 41% were born out of state, 1% were born outside of the United States and 1% were foreign born.