On October 4, 1858, the Sisters of Saint Joseph founded Mount Saint Joseph Academy for Young Ladies on the grounds of what is now Chestnut Hill College. The Mount, as it is fondly known by generations of graduates, is the oldest continuously operating Catholic girls' school in the Philadelphia area. Rooted in the sisters' maxim "on the education of women largely depends the future of society," the school continues to grow while maintaining its core Catholic mission. Mount Saint Joseph Academy follows the school from its boarding-school days at the Monticello mansion in Chestnut Hill, Philadelphia, to its modern 78-acre campus in Flourtown, Montgomery County, where girls in grades 9 through 12 receive a private, college-preparatory education in the tradition of excellence. On the momentous occasion of the school's 150th anniversary, Mount Saint Joseph Academy is a tribute to the Mount's rich history of service, academics, athletics, and the arts.