Altamont, IL has a population of 2,314 and is the 10,231st largest city in the United States. The population density is 1,633 per sq mi which is 635% higher than the Illinois average and 1703% higher than the national average. The median age in Altamont is 37 which is approximately 2% lower than the Illinois average of 37. In Altamont, 62% of the population over 15 years of age are married, 100% speak English and 0% speak Spanish. 85% of Altamont residents were born in Illinois, 14% were born out of state, 0% were born outside of the United States and 0% were foreign born.