Altenburg is a city in Perry County, Missouri, United States. The population was 352 at the 2010 census.
Altenburg is located at 37°37′53″N 89°34′53″W / 37.63139°N 89.58139°W / 37.63139; -89.58139 (37.631301, -89.581513).
According to the United States Census Bureau, the city has a total area of 1.05 square miles (2.72 km), all land.
As of the census of 2010, there were 352 people, 138 households, and 97 families residing in the city. The population density was 335.2 inhabitants per square mile (129.4/km). There were 152 housing units at an average density of 144.8 per square mile (55.9/km). The racial makeup of the city was 99.15% White, 0.28% Black or African American, and 0.57% from two or more races.
There were 138 households of which 39.9% had children under the age of 18 living with them, 58.7% were married couples living together, 6.5% had a female householder with no husband present, 5.1% had a male householder with no wife present, and 29.7% were non-families. 26.8% of all households were made up of individuals and 18.1% had someone living alone who was 65 years of age or older. The average household size was 2.55 and the average family size was 3.04.
The median age in the city was 37 years. 27% of residents were under the age of 18; 7.9% were between the ages of 18 and 24; 28.5% were from 25 to 44; 23% were from 45 to 64; and 13.6% were 65 years of age or older. The gender makeup of the city was 48.6% male and 51.4% female.
As of the census of 2000, there were 309 people, 126 households, and 86 families residing in the city. The population density was 323.4 people per square mile (124.3/km²). There were 140 housing units at an average density of 146.5 per square mile (56.3/km²). The racial makeup of the city was 99.35% White, and 0.65% from two or more races.
There were 126 households out of which 35.7% had children under the age of 18 living with them, 61.9% were married couples living together, 5.6% had a female householder with no husband present, and 31.0% were non-families. 27.8% of all households were made up of individuals and 16.7% had someone living alone who was 65 years of age or older. The average household size was 2.45 and the average family size was 3.05.
In the city the population was spread out with 25.6% under the age of 18, 6.8% from 18 to 24, 30.7% from 25 to 44, 18.8% from 45 to 64, and 18.1% who were 65 years of age or older. The median age was 36 years. For every 100 females there were 108.8 males. For every 100 females age 18 and over, there were 107.2 males.
The median income for a household in the city was $40,417, and the median income for a family was $46,136. Males had a median income of $33,125 versus $20,208 for females. The per capita income for the city was $19,174. None of the families and 5.0% of the population were living below the poverty line, including no under eighteen and 13.0% of those over 64.