HEBRON, N.H. -- From Aug. 20-24th, more than 200 girls, ages 9 to 13, are populating the Opus Dei-guided Camp Mattakeesett in Hebron, N.H., a one-week annual summer camp in its 17th year.

The camp began in 1992, when a group of women associated with Arnold Hall, the Opus Dei retreat and conference center in Pembroke, decided that it would be nice to have a positive place for girls to go to during the summer, said Rosemary Cook, a mother of nine and grandmother of 44, who has led the camp since its inception.

The campers combine regular summer camp activities with adoration of the Eucharist, daily Mass and the sacrament of reconciliation, she said. “We have swimming, boating and arts and crafts, but we try to weave the fun and the holy together.”

Other activities include a Camp Olympics competition, a find-the-counselor scavenger hunt and a dance party, she said. At noon the campers recite the Angelus.

Each cabin of 10 to 12 girls, plus a counselor with a counselor-in-training, will pray the rosary together daily, she said. “When they say the rosary, they usually will go outside or down by the water.”

This year’s location on Newfound Lake is one of many different places the camp has called home, Cook said. For one week every year, Camp Mattakeesett rents the grounds from another camp after it closes for the season.

“There is another Opus Dei camp for boys in Pennsylvania that has to do the same thing, but they have a lot of kids from the Boston-area. I always thought there would be a way to buy a camp, so we and others could use [it]. But, since I only have $3.50 to my name, I have to hope some rich person looking for something to do with their money will help us.”

A similar camp for girls is run in Maryland by her daughter Jennifer Kilmer, who has 10 children of her own. “She was a counselor with us in the beginning, but she has been doing her own camp for eight years,” said Cook.

Although Cook grew up on the same road as Arnold Hall, it took her a while to warm up to her neighbors.

“My father had warned me about them because he said they were a splinter group,” she said. But, during a very bad snowstorm in the late 1960s, as her family was stuck without heat or electricity, members of Opus Dei came by. “They came up in a sleigh and brought us hot cocoa, and I thought, well, maybe my father was wrong about them.”

During the week of camp, Cook said she would like to be out on a kayak or joining the activities, but most of her time is spent with four or five homesick girls.

“We almost never have anyone go home, maybe once every few years. But, there are some who have trouble being away from home,” she said. “The best part is when they get over it, and then when they are leaving they tell you: ‘I’m coming back next year!’ Wow, that is victory.”