Damiansville is a village in Clinton County, Illinois, United States. The population was 491 at the 2010 census, up from 368 in 2000.
Damiansville is located in southwestern Clinton County at 38°30′34″N 89°37′27″W / 38.50944°N 89.62417°W / 38.50944; -89.62417 (38.509534, -89.624278). Interstate 64 runs along the southern border of the village, with access from Exit 34, and leads 35 miles (56 km) west to St. Louis and 43 miles (69 km) east to Mount Vernon.
According to the 2010 census, Damiansville has a total area of 0.82 square miles (2.12 km), all land.
As of the census of 2000, there were 368 people, 125 households, and 103 families residing in the village. The population density was 1,522.8 people per square mile (592.0/km²). There were 130 housing units at an average density of 537.9 per square mile (209.1/km²). The racial makeup of the village was 97.01% White, 1.09% Native American, 1.09% Asian, and 0.82% from two or more races. Hispanic or Latino of any race were 0.82% of the population.
There were 125 households out of which 42.4% had children under the age of 18 living with them, 70.4% were married couples living together, 7.2% had a female householder with no husband present, and 16.8% were non-families. 10.4% of all households were made up of individuals and 3.2% had someone living alone who was 65 years of age or older. The average household size was 2.94 and the average family size was 3.21.
In the village, the population was spread out with 28.3% under the age of 18, 10.1% from 18 to 24, 32.9% from 25 to 44, 19.0% from 45 to 64, and 9.8% who were 65 years of age or older. The median age was 33 years. For every 100 females, there were 102.2 males. For every 100 females age 18 and over, there were 100.0 males.
The median income for a household in the village was $50,694, and the median income for a family was $53,250. Males had a median income of $36,806 versus $25,417 for females. The per capita income for the village was $18,985. About 3.8% of families and 5.8% of the population were below the poverty line, including 4.3% of those under age 18 and 13.0% of those age 65 or over.