Rigby, ID has a population of 4,028 and is the 7,421st largest city in the United States. The population density is 1,710 per sq mi which is 8863% higher than the Idaho average and 1787% higher than the national average. The median age in Rigby is 27 which is approximately 25% lower than the Idaho average of 36. In Rigby, 65% of the population over 15 years of age are married, 93% speak English and 3% speak Spanish. 77% of Rigby residents were born in Idaho, 18% were born out of state, 2% were born outside of the United States and 3% were foreign born.