American Falls, ID has a population of 4,351 and is the 7,060th largest city in the United States. The population density is 2,697 per sq mi which is 14034% higher than the Idaho average and 2877% higher than the national average. The median age in American Falls is 33 which is approximately 6% lower than the Idaho average of 36. In American Falls, 59% of the population over 15 years of age are married, 67% speak English and 32% speak Spanish. 63% of American Falls residents were born in Idaho, 23% were born out of state, 0% were born outside of the United States and 14% were foreign born.