Sheldon, IA has a population of 5,015 and is the 6,461st largest city in the United States. The population density is 1,076 per sq mi which is 1788% higher than the Iowa average and 1088% higher than the national average. The median age in Sheldon is 40 which is approximately 6% higher than the Iowa average of 38. In Sheldon, 65% of the population over 15 years of age are married, 94% speak English and 6% speak Spanish. 65% of Sheldon residents were born in Iowa, 30% were born out of state, 1% were born outside of the United States and 4% were foreign born.