Woodstock is the home of the historic Woodstock Opera House and Old McHenry County Courthouse. The city was named in 2007 as one of the nation's Dozen Distinctive Destinations 2007 by the National Trust for Historic Preservation.
As of the census of 2000, there were 20,151 people, 7,273 households, and 4,843 families residing in the city. The population density was 1,891.1 people per square mile (729.9/km²). There were 7,599 housing units at an average density of 713.1/sq mi (275.2/km²). The racial makeup of the city was 87.48% White, 1.06% African American, 0.23% Native American, 2.01% Asian, 7.69% from other races, and 1.52% from two or more races. Hispanic or Latino of any race were 19.01% of the population.
There were 7,273 households out of which 37.5% had children under the age of 18 living with them, 52.7% were married couples living together, 9.7% had a female householder with no husband present, and 33.4% were non-families. 27.3% of all households were made up of individuals and 9.2% had someone living alone who was 65 years of age or older. The average household size was 2.68 and the average family size was 3.30.
In the city the population was spread out with 27.9% under the age of 18, 10.2% from 18 to 24, 33.2% from 25 to 44, 18.9% from 45 to 64, and 9.8% who were 65 years of age or older. The median age was 32 years. For every 100 females there were 100.8 males. For every 100 females age 18 and over, there were 98.5 males.
The median income for a household in the city was $47,871, and the median income for a family was $54,408. Males had a median income of $40,137 versus $27,264 for females. The per capita income for the city was $23,210. About 5.3% of families and 7.2% of the population were below the poverty line, including 8.0% of those under age 18 and 3.0% of those age 65 or over.
23% of Woodstock residents age 25 and older have a bachelor's or advanced college degree.
Woodstock's railroad station is the second-to-the-last-stop on Metra's Union/Pacific Northwest Line, which originates in Chicago's Ogilvie Transportation Center in downtown Chicago.
U.S. Route 14 curves around Woodstock's southwest border, intersecting with Illinois Route 47 at Woodstock's southeast edge. Illinois Route 120 meets Route 47 approximately 1/4 mile northwest of Woodstock's Public Square.