From the National Registry of Historic Places Inventory -- Nomination Form:
"The Woodstock Square Historic District lies in the center of Woodstock, Illinois, county seat of McHenry County. Within its boundaries, clustered around the town square and the tracks of the Chicago and Northwestern Railroad, are found Woodstock's traditional governmental, social and commercial center: the old courthouse and jail, city hall, and the post office; the opera house, two social clubs, and a movie house; and the tightly packed facades of two- and three-story commercial buildings.
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The land rises gently from the railroad south along Benton to Cass and more sharply west from Benton through the square to the old courthouse. This imposing edifice is set on what was reputed to be the highest point in McHenry County: 373 feet above Lake Michigan and 954 feet above sea level - facts the early county commissioners thought worthy of carving on the courthouse's watertable.
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The courthouse cupola and the opera house tower dominate the square and, indeed, are visible from many parts of town.
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The streets surrounding the square retain their original brick paving.
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History
The first European settler arrived in the Woodstock area in 1834, the year after the village of Chicago, seventy miles to the east, was incorporated. The surrounding countryside, rolling hills of glacial deposit and loess, was covered with a patchwork of prairies, oak groves and hardwood forests, though this was soon to be transformed into farmland. Farming is still the major occupation and preoccupation of McHenry County, and rich dairy farms still surround the town of Woodstock, though suburban encroachment from Chicago has already reached the eastern part of the county.
Named for Col. William McHenry, a regimental commander during the Black Hawk War of 1832, McHenry County was created in 1836 from the northern and western protions of Cook County. The first county seat, McHenry, was located in the center of the county until Lake County was separated from McHenry County several years later, leaving the town of McHenry on the new eastern border. Thus, in 1844 Alvin Judd platted a new town in the county's center called, appropriately, Centerville, in the hopes that the county seat might be moved. The plat, a central square oriented to the compass points with streets originating at the centers of the four sides, the whole surrounded by rectangular grid, was recorded by George Dean in June, 1844. The scheme was successful, Centerville was named the new county seat, and on September 4, 1844 the county government moved to the new, one-story frame building constructed in the town square. Very soon (February, 1845) the name was changed to Woodstock at the suggestion of early settler Joel Johnson to honor his home town of Woodstock, Vermont.
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By mid-century the square was surrounded by a group of mostly detached, one- and two-story frame buildings, many displaying pattern-book Greek Revival details. The several hotels provided resting places for visitors with business at the courthouse, while the wide streets around the square were the scene of a farmer's market every Saturday. As early as May, 1853, the county commissioners discussed the need for a new courthouse and two years later appointed a committee to secure plans. Meanwhile, in order that the square could become a public park, the people of Woodstock purchased and donated to the county several properties on the west side of the square for the site of the new building. Opened on October 1, 1857 and built at a cost of $47,000, the Italianate structure was designed by Chicago architect John M. Van Osdel (1811-1892) and bears a striking resemblance to his Cook County Courthouse of 1853. The vacated frame courthouse burned shortly thereafter, and in 1858/9 the square was graded and planted in elm trees.
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In 1887, by which time the city had over 2,000 inhabitants, the county built a separate jail building for $17,000 just north of the courthouse. Two years later work had begun on the square's most impressive late nineteenth century structure: the opera house. This imposing Romanesque-styled building originally held, in addition to the 64-seat theatre, the city hall, the fire department, and the public library. The theatre has had an impressive history, including the summer of 1934 when Orson Welles produced five plays, among them Hamlet and MacBeth.