Altenburg, MO has a population of 508 and is the 19,438th largest city in the United States. The population density is 484 per sq mi which is 460% higher than the Missouri average and 434% higher than the national average. The median age in Altenburg is 33 which is approximately 13% lower than the Missouri average of 38. In Altenburg, 71% of the population over 15 years of age are married, 99% speak English and 0% speak Spanish. 86% of Altenburg residents were born in Missouri, 14% were born out of state, 0% were born outside of the United States and 0% were foreign born.