The Union School, built in 1885, was the home of the High School until 1914. The former Seminary building had deteriorated significantly and there was a demand for new educational facilities. It was located close to Philomethian St. and soon became known as the Philomethian Street School. The Seminary building was moved to make way for the new, Romanesque Revival style building. Large stones with the date 1885 and PUBLIC SCHOOLS were incorporated into the design of the building.
The building was soon overcrowded, so in 1892 four elementary classrooms and a 750 seat Assembly Hall (auditorium) in the Georgian Revival style were added at a cost of $16,000. In 1895, electric lights were installed in the building. A separate elementary school building was added later.
Students from Orange, Russell and Bainbridge rode horses or the Interurban to Chagrin to attend the new school. In 1907 Ohio rated the High School as a First Grade High School.