Rupert, ID has a population of 5,702 and is the 5,945th largest city in the United States. The population density is 2,770 per sq mi which is 14416% higher than the Idaho average and 2957% higher than the national average. The median age in Rupert is 30 which is approximately 17% lower than the Idaho average of 36. In Rupert, 57% of the population over 15 years of age are married, 63% speak English and 37% speak Spanish. 56% of Rupert residents were born in Idaho, 27% were born out of state, 0% were born outside of the United States and 17% were foreign born.