The College Preparatory School for Girls was founded by Mary Harlan Doherty in 1906. In 1916, Helen Lotspeich founded the Clifton Open-Air School. In 1927, another all-girls school called the Hillsdale School opened. A groundbreaking ceremony was held at the school's Deerfield Road location on June 6, 1927, ahead of the official opening on September 28, 1927. An announcement letter from the school's formulating committee stated, "A new Country Junior and Senior High School for girls has been organized in Cincinnati along modern educational lines." The Hillsdale School later merged to form the Hillsdale-Lotspeich School. In the summer of 1955, Hillsdale-Lotspeich obtained 20 acres of land on Red Bank Road, neighboring the existing Hillsdale School. The Hillsdale-Lotspeich School became partially co-educational in 1971. The new school's opening was marked with a convocation on September 19, 1974. Following the merger, the College Preparatory School's location in Madisonville continued to operate as an elementary school, while the Hillsdale campus operated all grades from preschool to twelfth grade. The school undertook two major construction projects in 2001. The 75-year-old upper school building on the Hillsdale campus was demolished to make way for a new building that would be more than twice as big. Upper school classes were held in temporary buildings for a year before the new building opened. Additionally, a 1920s building on the Doherty campus was demolished and replaced with Haile Hall, a new facility housing the preschool, kindergarten, and afterschool programs as well as Doherty's administration offices. In 2024, the school announced plans to close the Doherty campus by the beginning of the 2027–28 school year. They will be selling it to
Springer School and Center. Plans at the Hillsdale campus include demolition of the existing lower school building and replacement with a new, higher capacity building, expansion of the existing early childhood center, and renovation of Founders Hall, the school's cafeteria. ==Athletics==