It was mid-afternoon on an especially cold December day in 1883 when some people reported that they saw flames rising from the basement of the newly renovated courthouse. The flames quickly engulfed the structure and brought the Butler County courthouse, constructed in 1855, to ruins.
Planning for a new building began in 1884. The new courthouse would be a commodious and substantial building and serve as the main political center of Butler County for at least 50 years. James P. Bailey, of Pittsburgh, constructed the new courthouse in 1885. The new structure was a three story building built in the high Victorian Gothic style with some Romanesque accents included in the building's entrance. The designers along with members of the judicial system decided that the building needed to be sturdy, so the walls were 22 inches thick, built with sandstone and layered with brick from the basement to the top of the clock tower. Two of the most prominent features of Butler County's reconstructed courthouse are the architecture in the basement, which serves as an homage to the remains of the former building, and the large central clock tower that houses one of the most advanced mechanical clocks of the time period.
The population of Butler County was expected to grow over fifty years, but the population doubled in less than half that time. With the rise of industrialization and Pittsburgh steel industries, the courthouse was overrun by the mass amounts of cases. The call for expansion was answered in 1907, and aimed at extending the front walls of the courthouse by 15 feet and replacing the courthouse's single stairway with a central stairway. The upgrades also included new marble and metal framing, replacing the old wood structure. The two old, formal courtrooms were replaced by one large courtroom. These adjustments provided more room for the county’s official business.
The face of the courthouse has remained relatively unchanged besides the occasional face lift. The offices and resident positions have also stayed more or less the same. The courthouse has housed the offices of the Sheriff, the Prothonotary, Clerk of Court, and the many judges chambers throughout the years. The courthouse has also been used for extraneous duties such as a temporary school, concerts, and conferences.
Though the courthouse is an old structure, there is a relatively new mystery surrounding it. In 1955, a group of contractors were removing their equipment from the basement of the courthouse when they discovered an opening to a small stream beneath the building. This stream had fresh water in it. The mystery lies in the source of the water. Popular belief claims that the stream served as an early ventilation system. Whether the water is supplied or stagnant is still a question left open for debate, and has puzzled people for years.