Woodstock is a city in and the county seat of McHenry County, Illinois, United States, located 51 miles (82 km) northwest of Chicago. The population was 25,528 at the start of 2017. The city's downtown includes a historic, turn-of-the-century town square, which is anchored by the landmark Woodstock Opera House and the Old McHenry County Courthouse. The city was named one of the nation's Dozen Distinctive Destinations in 2007 by the National Trust for Historic Preservation.
Woodstock was originally known as Centerville because of its location at the geographic center of McHenry County. It was chosen as the county seat on September 4, 1843. Early settler Alvin Judd developed a plat for the town, which incorporated a two-acre public square, near which a 2-story frame courthouse and jail were constructed the following year by George C. Dean and Daniel Blair. In 1845, prominent resident Joel Johnson proposed that Centerville be given a more original name, and so the town was renamed Woodstock after Johnson's hometown of Woodstock, Vermont. (The town was listed as "Center" on the 1850 Federal Census, however.) In 1852, Woodstock was incorporated as a village with Judd as president. In response to a growing population following the end of the Civil War, Woodstock was incorporated as a city in 1873. John S. Wheat was elected as Woodstock's first mayor.