After six years of planning and preparation, the Northern Senior Center opened this week in St. Mary's County.

The $2 million building in Charlotte Hall will be the first activity center for the elderly in the northern portion of the county; senior centers operate in Leonardtown and Lexington Park.

Within its 12,000-square-foot space, the newest center includes a computer room, two craft rooms, an exercise room, a game room, a social room and a large auditorium known as the "Great Room," which filled with more than 200 people Tuesday morning for the opening celebration.

"You ladies have wanted this so badly," St. Mary's County commissioners President Thomas F. McKay (R-At Large) told the members of the Northern Senior Center Council, who were seated in the first few rows of folding chairs. "There can be no rainbow without first a cloud and a storm. . . . Today is your rainbow."

The demand for the senior-oriented services in St. Mary's and the rest of Southern Maryland is booming, state and local officials said. Between 2000 and 2030, the population of people older than 60 is projected to grow by more than 200 percent in Charles, Calvert and St. Mary's counties -- a rate that would rank those jurisdictions first, second and third in the state, respectively, according to the Maryland Department of Aging.

"It's a major retirement destination," said Gene Carter, director of the St. Mary's County Department of Aging.

The idea of the Northern Senior Center began to crystallize in 1999, when Patricia Myers, then a vice president with the 5th District Homemakers, began to hear at luncheon meetings that the seniors in that part of the county had nowhere to meet and participate in activities. A group of people came together to organize a petition drive and collected about 3,000 signatures in support of a center, said Myers, now the president of the Northern Senior Center Council.

But the project didn't come easily. Neighbors in Charlotte Hall protested the idea. Funding was difficult to secure. There were even delays while experts tried to figure out whether an endangered fern was growing on the site. It wasn't.

For a time, the seniors operated out of the Mount Zion United Methodist Church. Eventually, the county commissioners committed the bulk of the cost, and the state pitched in $600,000.

The center, built on a 40-acre site on Charlotte Hall Road, will be open five days a week and have four employees and a volunteer receptionist, Myers said. Seniors can take ceramics and sewing classes, play pool and throw darts, exercise on the treadmill, take yoga, perform in the choir group, go line dancing and hold meetings for local groups.

"Our goal is to help the seniors keep their minds and bodies active," Myers said.

Carol Baker, deputy secretary in the Maryland Department of Aging, said that in the future, senior centers in the state will continue to have more diverse services, including retail stores, dry cleaners and, instead of one drab dish for dinner, "something that looks more like a food court."

For now, the Northern Senior Center seemed to please those at the opening just fine.

"We're all thrilled," said Sally Wood, 68, of Lexington Park. "It's taken a long time to get it."