2020 census thumb|right|2022 US Census population pyramid for Appanoose County from ACS 5-year estimates The 2020 census recorded a population of 12,317 in the county, with a population density of . 96.66% of the population reported being of one race. 93.03% were non-Hispanic White, 0.61% were Black, 1.88% were Hispanic, 0.19% were Native American, 0.57% were Asian, 0.06% were Native Hawaiian or Pacific Islander and 3.66% were some other race or more than one race. There were 6,306 housing units of which 5,320 were occupied.
2020 census thumb|right|2022 US Census population pyramid for Appanoose County from ACS 5-year estimates The 2020 census recorded a population of 12,317 in the county, with a population density of . 96.66% of the population reported being of one race. 93.03% were non-Hispanic White, 0.61% were Black 1.88% were Hispanic, 0.19% were Native American, 0.57% were Asian, 0.06% were Native Hawaiian or Pacific Islander and 3.66% were some other race or more than one race. There were 6,306 housing units of which 5,320 were occupied.