Plattsburg, MO has a population of 2,428 and is the 9,939th largest city in the United States. The population density is 674 per sq mi which is 674% higher than the Missouri average and 644% higher than the national average. The median age in Plattsburg is 42 which is approximately 11% higher than the Missouri average of 38. In Plattsburg, 61% of the population over 15 years of age are married, 95% speak English and 4% speak Spanish. 67% of Plattsburg residents were born in Missouri, 31% were born out of state, 0% were born outside of the United States and 2% were foreign born.