Thayer is a city in Oregon County, Missouri, United States.

[6] Thayer is considered a railroad town, as it was laid out in 1882 to be a division point.

[7] Currently, the Burlington Northern Santa Fe railroad travels through town.

According to the United States Census Bureau, the city has a total area of 2.44 square miles (6.32 km2), all land.

There were 1,140 housing units at an average density of 467.2 per square mile (180.4/km2).

The racial makeup of the city was 96.39% White, 0.09% Black or African American, 0.94% Native American, 0.36% Asian, 0.04% Native Hawaiian or Pacific Islander, 0.18% from other races, and 2.01% from two or more races.

36.1% of all households were made up of individuals, and 16.6% had someone living alone who was 65 years of age or older.

36.1% of all households were made up of individuals, and 19.5% had someone living alone who was 65 years of age or older.