Seymour, MO has a population of 1,909 and is the 11,289th largest city in the United States. The population density is 691 per sq mi which is 700% higher than the Missouri average and 663% higher than the national average. The median age in Seymour is 39 which is approximately 1% higher than the Missouri average of 38. In Seymour, 59% of the population over 15 years of age are married, 100% speak English and 0% speak Spanish. 76% of Seymour residents were born in Missouri, 24% were born out of state, 0% were born outside of the United States and 0% were foreign born.