Union is a village in McHenry County, Illinois, United States. The population was 580 at the 2010 census, up from 576 in 2000. History A post office called Union has been in operation since 1852. The village was named for the federal union of the United States. Geography Union is located at (42.235237, -88.542379). According to the 2010 census, Union has a total area of , all land. Demographics At the 2000 census there were 576 people, 204 households, and 158 families living in the village. The population density was . There were 208 housing units at an average density of . The racial makeup of the village was 98.09% White, 0.35% Native American, 0.87% from other races, and 0.69% from two or more races. Hispanic or Latino of any race were 3.99%. Of the 204 households 37.7% had children under the age of 18 living with them, 63.7% were married couples living together, 9.3% had a female householder with no husband present, and 22.5% were non-families. 15.7% of households were one person and 6.4% were one person aged 65 or older. The average household size was 2.82 and the average family size was 3.15. The age distribution was 28.0% under the age of 18, 7.5% from 18 to 24, 34.2% from 25 to 44, 19.3% from 45 to 64, and 11.1% 65 or older. The median age was 36 years. For every 100 females, there were 92.6 males. For every 100 females age 18 and over, there were 97.6 males. The median household income was $56,528 and the median family income was $57,500. Males had a median income of $38,393 versus $25,536 for females. The per capita income for the village was $21,218. About 5.8% of families and 5.2% of the population were below the poverty line, including 2.9% of those under age 18 and 16.7% of those age 65 or over. Points of interest Union was the site of the world's first fully automatic substation, on the current site of the water tower just east of Main Street. Union is also the home to the Illinois Railway Museum and the McHenry County Historical Society. It is also the home of Donley's Wild West Town amusement park and the site of the oldest and largest Antique Phonograph Show in the world. Donley's Wild West Town is now run by the Onesti entertainment group. Notable person Red Kelly, right fielder