Rexburg, ID has a population of 27,114 and is the 1,594th largest city in the United States. The population density is 2,796 per sq mi which is 14555% higher than the Idaho average and 2986% higher than the national average. The median age in Rexburg is 23 which is approximately 36% lower than the Idaho average of 36. In Rexburg, 56% of the population over 15 years of age are married, 89% speak English and 7% speak Spanish. 37% of Rexburg residents were born in Idaho, 56% were born out of state, 2% were born outside of the United States and 5% were foreign born.