Preston, IA has a population of 981 and is the 15,280th largest city in the United States. The population density is 1,019 per sq mi which is 1769% higher than the Iowa average and 1025% higher than the national average. The median age in Preston is 39 which is approximately 3% higher than the Iowa average of 38. In Preston, 65% of the population over 15 years of age are married, 99% speak English and 0% speak Spanish. 91% of Preston residents were born in Iowa, 6% were born out of state, 1% were born outside of the United States and 1% were foreign born.