The building complex was formerly Smedley's Hydro, a hydrotherapy spa and hotel built on Matlock Bank by John Smedley in 1853. Matlock had developed as a spa town after thermal springs were discovered, and Smedley's was the largest hydro in the town.
Smedley's Hydro closed in the 1950s, and the complex was purchased in 1955 by the Derbyshire County Council to use as its headquarters. The County Hall includes the main council chamber and several committee rooms, as well as the offices of many of the council's departments.
The County Hall is also marketed as a venue for conferences, weddings and other events. It boasts an in-house catering team, a large bar for refreshments and function suites.