McHenry County's first commissioners met in this building on August 5th, 1840. The original structure stood on the Court Street side of the public square, now Veterans Memorial Park, as McHenry County's first courthouse. McHenry County split from Cook County in 1836, at first comprising both Lake and McHenry counties, with the village of McHenry as the centrally located county seat. Lake and McHenry counties divided in 1839. In 1843, the county seat was relocated to Centerville, now Woodstock. In 1844, the government auctioned the courthouse to Horace Long, who moved it to this location on Riverside Drive, originally Water Street, for use as a tavern and hotel.