Alto Pass, IL has a population of 382 and is the 21,122nd largest city in the United States. The population density is 179 per sq mi which is 19% lower than the Illinois average and 98% higher than the national average. The median age in Alto Pass is 40 which is approximately 8% higher than the Illinois average of 37. In Alto Pass, 51% of the population over 15 years of age are married, 81% speak English and 18% speak Spanish. 71% of Alto Pass residents were born in Illinois, 19% were born out of state, 1% were born outside of the United States and 9% were foreign born.