Altenburg
- County:
- Cape Girardeau County
- County Seat:
- No
- Area (mi²):
- 1.05
- State:
- Missouri
Altenburg is a city located in Cape Girardeau County, Missouri. Altenburg has a 2026 population of 337. Altenburg is currently declining at a rate of -0.3% annually and its population has decreased by -1.46% since the most recent census, which recorded a population of 342 in 2020.
The median household income in Altenburg is $66,250 with a poverty rate of 6.1%. The median age in Altenburg is 41.6 years: 41.8 years for males, and 40.3 years for females. For every 100 females there are 81.3 males.