After more than a century as a Mankato landmark, big changes may be in store for the School Sisters of Notre Dame campus on Good Counsel Hill.

Citing the need to raise money for its mission, as well as care for its aging sisters, the religious congregation has announced plans to sell the 135-acre campus on a bluff that overlooks downtown Mankato and the Minnesota River.

"We have developed mutual relationships with generations of people in the Mankato area," the School Sisters said in a statement. "Letting go of sacred and treasured spaces is a historic journey for us; one that we are committed to do in prayer, dialogue and collaboration."

The School Sisters are also divesting themselves of three other properties in the United States.

It's unusual for such a large chunk of land to become available in a mature city, although the size of the marketable property was trimmed back with the announcement that Loyola Catholic School — which is housed on the campus — would buy about 55 acres for an undisclosed price.

Still, Mankato city officials are excited about the chance at redevelopment while cautious about the amount of planning it will take to reach the finish line.

"It's a great opportunity. But you have to go through the process to get to a great product," said Paul Vogel, Mankato's director of community development. "You can get sideways very easily. Focusing on a sound process to get to a good end result will be crucial."

The sisters have been part of Mankato since 1865, members of a European religious congregation that arrived to minister to the area's German Catholic population. The group was founded in the 1500s to provide free education to disadvantaged girls.

In 1912, Good Counsel Academy, a school for girls, opened on the hill and the campus expanded over the years to its present size.

The sisters, in Mankato and elsewhere, have a history of participating in causes aimed at promoting social justice.

In addition, hundreds of School Sisters in the United States have volunteered to be part of a long-term study of Alzheimer's disease, undergoing annual tests and donating their brains to science upon death.

The organization currently has more than 2,100 sisters worldwide, with 132 living on the Mankato campus. It's uncertain where the sisters will live after the campus transitions, said Sister Debra Marie Sciano, provincial leader of the group's Central Pacific Province.

"We are looking for a place our sisters can live together, if this is possible," she said. "While it is our preference to remain in the Mankato area, that is unknown at this time."

In recent years, the group went through a similar process with the divestment of its campus in Elm Grove, Wis., near Milwaukee. By all accounts, it was handled very well, Vogel said.

"It looks like they undertook a very comprehensive and careful planning process," he said. "And that took several years."

It's too early to say what might happen with the property, Vogel added. When a new owner appears, the city will have to balance its goals of affordability, community engagement and stewardship, both of the environment and of existing neighborhoods that adjoin the campus.

Sciano said the sisters hope to sell the property to "a like-minded person or organization who shares our commitment to transform the world through education, giving special emphasis to women, young people and those who are poor.

"Our hopes and prayers are that the Hill will continue to serve the greater Mankato area in a manner that is consistent with our history, mission and values."

John Reinan • 612-673-7402