Callao is a city in Macon County, Missouri, United States.

[10] The Johnson Morrow House was listed on the National Register of Historic Places in 1994.

Missouri Route 3 passes through the center of Callao as Chestnut Street, leading north 33 miles (53 km) to Kirksville and south 24 miles (39 km) to Clifton Hill.

According to the U.S. Census Bureau, Callao has a total area of 0.52 square miles (1.35 km2), all land.

23.2% of all households were made up of individuals, and 5.4% had someone living alone who was 65 years of age or older.

The racial makeup of the city was 99.31% White, 0.34% Native American, and 0.34% from two or more races.

24.8% of all households were made up of individuals, and 12.8% had someone living alone who was 65 years of age or older.

About 18.7% of families and 26.1% of the population were below the poverty line, including 65.3% of those under the age of eighteen and 9.6% of those 65 or over.