Boulder, UT has a population of 165 and is the 25,288th largest city in the United States. The population density is 8 per sq mi which is 77% lower than the Utah average and 91% lower than the national average. The median age in Boulder is 45 which is approximately 48% higher than the Utah average of 30. In Boulder, 38% of the population over 15 years of age are married, 88% speak English and 3% speak Spanish. 41% of Boulder residents were born in Utah, 59% were born out of state, 0% were born outside of the United States and 0% were foreign born.