|Area||0.27 sq mi (1 km2)|
|- land||0.27 sq mi (1 km2)|
|- water||0.00 sq mi (0 km2)|
|Density||557.0 / sq mi (215 / km2)|
|- summer (DST)||CDT (UTC-5)|
|Wikimedia Commons: Marietta, Illinois|
Marietta is located at (40.501508, -90.393168).
According to the 2010 census, the village has a total area of 0.27 square miles (0.70 km2), all land.
As of the census of 2000, there were 150 people, 56 households, and 40 families residing in the village. The population density was 557.0 people per square mile (214.5/km²). There were 59 housing units at an average density of 219.1 per square mile (84.4/km²). The racial makeup of the village was 98.67% White and 1.33% Native American.
There were 56 households out of which 32.1% had children under the age of 18 living with them, 62.5% were married couples living together, 7.1% had a female householder with no husband present, and 26.8% were non-families. 23.2% of all households were made up of individuals and 3.6% had someone living alone who was 65 years of age or older. The average household size was 2.68 and the average family size was 3.05.
In the village the population was spread out with 20.7% under the age of 18, 16.0% from 18 to 24, 24.0% from 25 to 44, 28.0% from 45 to 64, and 11.3% who were 65 years of age or older. The median age was 32 years. For every 100 females there were 100.0 males. For every 100 females age 18 and over, there were 108.8 males.
The median income for a household in the village was $40,000, and the median income for a family was $38,750. Males had a median income of $30,893 versus $16,250 for females. The per capita income for the village was $15,662. There were none of the families and 2.7% of the population living below the poverty line, including no under eighteens and none of those over 64.
- "US Gazetteer files: 2010, 2000, and 1990". United States Census Bureau. 2011-02-12. Retrieved 2011-04-23.
- "2010 Census U.S. Gazetteer Files for Places – Illinois". United States Census. Retrieved 2012-10-13.
- "American FactFinder". United States Census Bureau. Retrieved 2008-01-31.