|Area||1.29 sq mi (3 km2)|
|- land||1.29 sq mi (3 km2)|
|- water||0.00 sq mi (0 km2)|
|Density||348.3 / sq mi (134 / km2)|
|Incorporated||February 15, 1865|
|- summer (DST)||CDT (UTC-5)|
|Wikimedia Commons: Mason, Illinois|
Mason is an incorporated town in Effingham County, Illinois, United States. The population was 396 at the 2000 census. It was named after Mayor Roswell Mason of Chicago, who built the Central Illinois railroad.
Mason is located at (38.952398, -88.626490).
According to the 2010 census, the town has a total area of 1.29 square miles (3.3 km2), all land.
As of the census of 2000, there were 396 people, 147 households, and 103 families residing in the town. The population density was 348.3 people per square mile (134.1/km²). There were 160 housing units at an average density of 140.7/sq mi (54.2/km²). The racial makeup of the town was 98.23% White, 0.25% Native American, 0.76% from other races, and 0.76% from two or more races. Hispanic or Latino of any race were 2.27% of the population.
There were 147 households out of which 34.0% had children under the age of 18 living with them, 60.5% were married couples living together, 4.1% had a female householder with no husband present, and 29.3% were non-families. 25.9% of all households were made up of individuals and 14.3% had someone living alone who was 65 years of age or older. The average household size was 2.69 and the average family size was 3.15.
In the town the population was spread out with 28.3% under the age of 18, 4.8% from 18 to 24, 33.6% from 25 to 44, 22.7% from 45 to 64, and 10.6% who were 65 years of age or older. The median age was 35 years. For every 100 females there were 118.8 males. For every 100 females age 18 and over, there were 107.3 males.
The median income for a household in the town was $40,441, and the median income for a family was $41,797. Males had a median income of $26,607 versus $18,333 for females. The per capita income for the town was $13,392. About 5.9% of families and 6.1% of the population were below the poverty line, including 4.2% of those under age 18 and 17.1% of those age 65 or over.
- Lowell Bayles, air race pilot
- Ada Kepley, author and first American woman to graduate law school owned a farm in Mason township.
- Illinois Regional Archives Depository System. "Name Index to Illinois Local Governments". Illinois State Archives. Illinois Secretary of State. Retrieved 2 May 2013.
- "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.