Callao
- County:
- Macon County
- County Seat:
- No
- Area (mi²):
- 0.517
- State:
- Missouri
Callao is a city located in Macon County, Missouri. Callao has a 2026 population of 246. Callao is currently declining at a rate of -0.81% annually and its population has decreased by -1.6% since the most recent census, which recorded a population of 250 in 2020.