Grantsville, UT has a population of 9,862 and is the 3,973rd largest city in the United States. The population density is 263 per sq mi which is 683% higher than the Utah average and 191% higher than the national average. The median age in Grantsville is 32 which is approximately 6% higher than the Utah average of 30. In Grantsville, 63% of the population over 15 years of age are married, 94% speak English and 2% speak Spanish. 70% of Grantsville residents were born in Utah, 27% were born out of state, 0% were born outside of the United States and 2% were foreign born.