More common, she said, was the kind of housing where residents prepaid for long-term care — which in some cases they never needed.

The size of Charlestown also set it apart, with most other continuing-care communities having several hundred residents rather than more than 2,000. That allowed an economy of scale.

"John Erickson's vision was the middle-aged schoolteacher could afford to go there," Roach said. "The schoolteacher who had a good pension plan, that is, and a house that was paid for."

Currently, according to Charlestown, residents pay a deposit of about $90,000 to $600,000 to move into the campus, refundable after they move out or die, and monthly fees that range from $1,200 to $3,400.

Roach said her department's audits show Charlestown is in good financial shape, and even during its bankruptcy and reorganization, residents barely noticed a difference.

The financial woes were the result of "a perfect storm" of cascading market problems, said Kevin Heffner, who directs professional education at UMBC's Erickson School for Management of Aging Services — which was founded with a $5 million donation by Erickson that was matched by the state.

Heffner said Erickson was in the midst of an aggressive expansion when the housing market crashed. That prompted its largest potential market — retirees who normally might sell their houses to raise cash for the entrance fee to a retirement community — to instead stay put. As customer demand fell, banks grew wary and credit markets collapsed.

Now the company faces a changing marketplace, Heffner said, as the nation's baby boomers approach a time when they will need senior housing but likely will have different tastes than their parents — and perhaps less secure bank accounts.

"They will have high expectations, they'll want more diversified activities," Heffner said. "They'll have higher expectations but a lower ability to pay for them."

Heffner said the trend of longer life expectancies means seniors generally will stay in their own homes for longer, and only enter a retirement community — if they do so at all — when older and perhaps frailer.

He said Charlestown should be able to adapt to a changing population because it offers a range of options in housing and meal plans, activities and other amenities. But it may have to change its model, he said, of a big entrance fee that is 100 percent refundable when the resident leaves or dies to one that has a lower upfront cost that may be less than fully returned.

For Thursday's celebration, members of the community and corporate officials celebrated both Charlestown's past and looked forward to its future.

Del. Steven J. DeBoy read proclamations from the governor and General Assembly, and noted his own ties to Charlestown: His mother-in-law lives there and his now-grown children worked in the dining room as teenagers.

Growing up in nearby Arbutus, DeBoy remembered when the site was the St. Charles Seminary, and seeing priests playing baseball in the field. He reminisced about how, after the seminary closed, the Baltimore Colts practiced on the grounds.

Remaining from the site's seminary days is Our Lady of the Angels Chapel, with a soaring 80-foot dome and beautiful stained glass and statuary. Coincidentally, it too is celebrating a milestone this year, Erickson noted on Thursday: ground was broken for the chapel 100 years ago.

Which makes Charlestown at 30 seem downright youthful.

"I hope I can make the 50th [anniversary]," Erickson told the crowd. "What do you think?"