Troy is a city in Madison County, Illinois, United States. The population was 9,888 at the 2010 census.
Troy is located at 38°43′45″N 89°53′30″W / 38.72917°N 89.89167°W / 38.72917; -89.89167 (38.729236, -89.891733).
According to the 2010 census, Troy has a total area of 5.349 square miles (13.85 km), of which 5.29 square miles (13.70 km) (or 98.9%) is land and 0.059 square miles (0.15 km) (or 1.1%) is water.
As of the census of 2000, there were 8,524 people, 3,100 households, and 2,356 families residing in the city. The population density was 2,037.6 people per square mile (787.4/km²). There were 3,201 housing units at an average density of 765.2 per square mile (295.7/km²). The racial makeup of the city was 95.48% White, 1.48% African American, 0.32% Native American, 0.70% Asian, 0.38% from other races, and 1.64% from two or more races. Hispanic or Latino of any race were 1.49% of the population.
There were 3,100 households out of which 45.2% had children under the age of 18 living with them, 60.1% were married couples living together, 12.5% had a female householder with no husband present, and 24.0% were non-families. 19.5% of all households were made up of individuals and 6.8% had someone living alone who was 65 years of age or older. The average household size was 2.75 and the average family size was 3.16.
In the city, the population was spread out with 30.2% under the age of 18, 8.6% from 18 to 24, 34.3% from 25 to 44, 19.2% from 45 to 64, and 7.7% who were 65 years of age or older. The median age was 33 years. For every 100 females, there were 96.0 males. For every 100 females age 18 and over, there were 91.5 males.
The median income for a household in the city was $53,720, and the median income for a family was $59,643. Males had a median income of $41,705 versus $27,542 for females. The per capita income for the city was $21,174. About 2.1% of families and 3.4% of the population were below the poverty line, including 3.4% of those under age 18 and 4.5% of those age 65 or over.
Troy Illinois neighborhoods include: Avalon, Bass, Berkshire Estates, Fairoaks, H&R Recruitment, Shadowcreek, Shadow Wood Plus, Silver Creek, Springvalley Rd, Staunton Rd, Steelecrest, Stonebriar, Taylor Lakes & Hazel, Tramore, Troy, Turtle Creek/Meadowbrooke, Twin Lakes