Union Hill is a village in Kankakee County, Illinois, United States. The population was 58 at the 2010 census. It is included in the Kankakee-Bradley, Illinois Metropolitan Statistical Area.

The settlement of the town is accredited to brothers Cornelius and John E. Schobey. With the second believed to be the town's founder when he moved to neighboring Essex Township in 1854. John Schobey opened a post office in 1861 during the start of the civil war. This inspired Mr. Schobey to make it so the settlements name had the word "union" included. After some trial and error the area became known as Union Hill around the same time. The Indiana, Illinois and Iowa Railroad (now the Kankakee Belt Route) was built through the area in 1882, which triggered the expansion of the town.

Union Hill was possibly incorporated as a village in 1903 or 1904.

Union Hill is located in western Kankakee County. It is 15 miles (24 km) west of Kankakee, the county seat, and 6 miles (10 km) northwest of Herscher.

According to the 2010 census, Union Hill has a total area of 0.05 square miles (0.13 km), all land.

Historical population

Census	Pop.	Note	%±
1950	138		—
1960	80		−42.0%
1970	85		6.3%
1980	82		−3.5%
1990	37		−54.9%
2000	66		78.4%
2010	58		−12.1%
2020	55		−5.2%
U.S. Decennial Census

As of the census of 2000, there were 66 people, 28 households, and 19 families residing in the village. The population density was 1,417.9 inhabitants per square mile (547.5/km). There were 29 housing units at an average density of 623.0 per square mile (240.5/km). The racial makeup of the village was 98.48% White, and 1.52% from two or more races.

There were 28 households, out of which 35.7% had children under the age of 18 living with them, 60.7% were married couples living together, 7.1% had a female householder with no husband present, and 28.6% were non-families. 28.6% of all households were made up of individuals, and 7.1% had someone living alone who was 65 years of age or older. The average household size was 2.36 and the average family size was 2.90.

In the village, the population was spread out, with 21.2% under the age of 18, 6.1% from 18 to 24, 34.8% from 25 to 44, 30.3% from 45 to 64, and 7.6% who were 65 years of age or older. The median age was 37 years. For every 100 females, there were 88.6 males. For every 100 females age 18 and over, there were 92.6 males.

The median income for a household in the village was $28,125, and the median income for a family was $46,667. Males had a median income of $28,250 versus $14,583 for females. The per capita income for the village was $21,371. None of the population is below the poverty line.