Montpelier, ID has a population of 2,519 and is the 9,796th largest city in the United States. The population density is 1,087 per sq mi which is 5595% higher than the Idaho average and 1099% higher than the national average. The median age in Montpelier is 37 which is approximately 2% higher than the Idaho average of 36. In Montpelier, 65% of the population over 15 years of age are married, 97% speak English and 1% speak Spanish. 64% of Montpelier residents were born in Idaho, 33% were born out of state, 0% were born outside of the United States and 3% were foreign born.