John W. Hallahan Catholic Girls' High School is an all-girls Roman Catholic high school located in Philadelphia, Pennsylvania, United States within the Archdiocese of Philadelphia. It is the country's first all-girls diocesan Catholic high school.

How old is Hallahan High?

Hallahan Catholic Girls' High School in 1925. The school had been built with a capacity of 1,000 students.

Who was Hallahan High School named after?

Mary McMichan were the leaders in the founding five “High School Centres” in 1901 which paved the way for the building of Catholic Girls High School in 1911. Upon the death of Mary McMichan, the name of the school was changed to John W. Hallahan Catholic Girls' High School in honor of her brother, as she requested.