Twin Falls, ID has a population of 46,623 and is the 887th largest city in the United States. The population density is 2,443 per sq mi which is 12705% higher than the Idaho average and 2597% higher than the national average. The median age in Twin Falls is 33 which is approximately 8% lower than the Idaho average of 36. In Twin Falls, 60% of the population over 15 years of age are married, 84% speak English and 10% speak Spanish. 52% of Twin Falls residents were born in Idaho, 37% were born out of state, 1% were born outside of the United States and 9% were foreign born.