John W. Hallahan Catholic Girls’ High School graduated its last class this month and closed its doors forever — but alumnae and supporters of the school have plans for a new, independent school to replace it, potentially opening this fall.

Officials are expected to announce Monday the forthcoming “Center City Girls’ Academy” to take Hallahan’s spiritual place in the city’s educational landscape, if not its actual name. Plans to name the school after Mary Hallahan McMichan — whose 1908 donation made Hallahan, the nation’s oldest all-girls’ diocesan high school, possible — have been at least temporarily blocked by the Archdiocese of Philadelphia.

In a cease and desist letter sent to the Friends of Hallahan in May, an archdiocese lawyer directed the group to stop using the Hallahan name — it had previously planned to open the “Mary Hallahan McMichan Academy.”

Using McMichan’s name “or legacy with any school undoubtedly conveys the impression the school is a Catholic school notwithstanding the fact that Friends of Hallahan cannot create a Catholic school under canon law,” lawyer Kevin R. Boyle wrote. “The sole authority to do so rests with the Archbishop of Philadelphia.”

Separately, the archdiocese is temporarily prohibited from selling or transferring the Hallahan building, at 19th and Wood Streets, by court order after a legal challenge from the supporters group, which also wants a full accounting of how the gifts of McMichan and others have been spent. A Tuesday hearing is scheduled in Orphans Court.

In the meantime, Nan Gallagher is busy making plans — filing articles of incorporation, finalizing details on a building rental, working on the particulars of a school she’s hopeful could open in Center City in September or October. Gallagher, a former president of Hallahan, will be president of the new school’s board.

» READ MORE: Two Catholic schools are fighting for their lives. Can Hallahan and McDevitt pull off a miracle? (from December 2020)

Retired for 10 years, Gallagher isn’t a Hallahan graduate herself; she attended another Philadelphia Catholic girls’ school, St. Hubert’s. But she was moved by the Friends of Hallahan group’s quest, and she’s dedicated her life to its mission.

“The belief in the value of educating women is alive and well,” Gallagher said. “There is no greater cause. When we educate women, we create a better society.”

The archdiocese ordered Hallahan and Bishop McDevitt High Schools closed after a system-wide planning process that officials said showed years of sluggish enrollment and financial problems. The long-range aim, they said, was to bolster the health of other Catholic high schools in the system. But Hallahan alumni say they were blindsided by the closure, and not given adequate opportunity to fight for the school.

Church officials do not believe that the Friends of Hallahan have any legal standing and think that its case “lacks foundation in law as well as fact,” Kenneth Gavin, a spokesperson for the archdiocese, said in a statement. Gavin said McMichan’s donation paid for construction of the Hallahan building and no money remained; money given in 1976, after McMichan’s daughter’s death, is “part of the funds which would be used to benefit Hallahan students over the next three years.”

“Serving as partners in the formation of our young people in a Catholic tradition is a sacred trust which we treasure,” Gavin said. “We will continue to utilize every available resource in support of the families who rely on us and remain grateful for their belief in the value of our schools.”

Gallagher said the new Center City school might have religious affiliation, if a sponsoring order signs on, but will likely be nonsectarian. The group is relying on donors to bankroll it; Gallagher said she believes they will need to raise “a few million, at minimum” but is confident in the deep pockets of those who have expressed interest in a rebooted Hallahan.

Two archdiocesan all-girls’ schools remain, Little Flower in Hunting Park and St. Hubert’s in Northeast Philadelphia, plus other independent private girls’ schools, but Hallahan was different, Gallagher said — diverse, and located in Center City, with easy access to the cultural and business opportunities that allows.

“To educate young women in that environment is far superior to other locations,” Gallagher said. “It gives them opportunities they will not have in other places, in other buildings.”

Starting a school in a matter of months will be tough, Gallagher acknowledged, but she said it’s possible. She said the school would likely start small but has received considerable interest from the community.

Gavin, the spokesperson for the archdiocese, said 72% of Hallahan students had committed to transferring to other Catholic schools in the system.

Gallagher said she’s in a tricky spot as a practicing Catholic pursuing a path opposed by the archdiocese.

“I have a very deep faith,” said Gallagher. “But my mission in life has always been to educate young women, and sometimes, God directs us in different ways.”