Stillman Valley is a village in Marion Township, Ogle County, Illinois, United States. It lies east of Byron, south of Rockford and west of Davis Junction. The population was 1,120 at the 2010 census, up from 1,048 in 2000. The village is located on the Iowa, Chicago and Eastern Railroad, on the old Chicago Great Western Railway before it merged and was pulled up. Also, Illinois Route 72 runs through the village. It is near the site of the first battle of the Black Hawk War of 1832. The war memorial for the Battle of Stillman’s Run is located in this village.
According to the 2010 census, Stillman Valley has a total area of 0.54 square miles (1.40 km), all land.
As of the census of 2000, there were 1,048 people, 395 households, and 295 families residing in the village. The population density was 735.7 /sq mi (284.1 /km²). There were 417 housing units at an average density of 292.7 per square mile (113.0/km²). The racial makeup of the village was 97.23% White, 0.29% African American, 0.67% Native American, 0.38% Asian, 0.48% from other races, and 0.95% from two or more races. Hispanic or Latino of any race were 1.43% of the population.
There were 395 households out of which 39.2% had children under the age of 18 living with them, 61.5% were married couples living together, 10.9% had a female householder with no husband present, and 25.3% were non-families. 23.3% of all households were made up of individuals and 10.1% had someone living alone who was 65 years of age or older. The average household size was 2.65 and the average family size was 3.14.
In the village, the population was spread out with 30.5% under the age of 18, 6.5% from 18 to 24, 31.3% from 25 to 44, 20.1% from 45 to 64, and 11.5% who were 65 years of age or older. The median age was 35 years. For every 100 females, there were 90.2 males. For every 100 females age 18 and over, there were 90.6 males.
The median income for a household in the village was $46,845, and the median income for a family was $54,792. Males had a median income of $36,635 versus $28,250 for females. The per capita income for the village was $21,036. About 4.6% of families and 4.6% of the population were below the poverty line, including 4.5% of those under age 18 and 5.7% of those age 65 or over. They are state champions in high school football 1999, 2000, 2003, 2009, and 2013.