I came to Grindstone as a young teenager in the mid-1980s, attending the annual summer camps run by the nonprofit cooperative the Quakers put together to manage the island. The camps’ explicit mission was to train a new generation of activists, another step on the ladder that they had climbed, through trade unionism, farmers’ unions, suffragism and feminism, to antiwar activism. Grindstone was full of kids like me: red-diaper babies who attended alternative public schools in Toronto, Kingston and Ottawa, who could rhyme the classic protest chant “one-two-three-four” with the facility of lifelong practice.

Today it sounds hopelessly idealistic. But in the ’80s, Grindstone was a perfect incubator for young activists. With its quiet paths, crisp lake swimming and isolated spots with names like Moonwatcher’s Point, the Grindstone experience was one part lazing around and chatting, one part intense, practical instruction. The Victorian cottages we slept in had once housed the political elites of Ottawa society and their celebrity friends. Now they were ours.

I’ve always been an early riser, and it was on Grindstone that I became addicted to sunrises, swimming around the island to catch them on the still lake amid the loon calls, then rushing in a shiver back to my cabin to change for breakfast and morning meeting on the broad, shaded porch of the main lodge. As I graduated out of the summer camps, I became active in the maintenance and management of the island, volunteering in the kitchens and serving on the co-op’s board.

When the co-op’s finances crashed with the late-1980s recession, we sold the island to a dentist from Kingston who planned to commute by small pontoon plane. I was devastated.

Today, Grindstone is the private home of David Bearman and Jennifer Trant — museum technology pioneers who fell in love with the island the first time they saw it, immediately dissolved their successful consultancy and took up residence there, running small conferences for people interested in museums and the web. Five years ago my family and I were their guests. The island felt haunted by the ghosts of the friends I’d made there and the dreams we’d shared.

It has been 25 years since I left Grindstone on its final weekend as a social justice education center, and not a week goes by without my yearning for it with a kind of joy and sorrow that is sunk very deep in my heart. I visit it in my dreams, and in the photo feeds from its current owners; when I see them at museum conferences, I demand to know all the minutiae of the island’s upkeep, which trees survived the winter storms and what color they’re painting the porch this year.

I live in Burbank, Calif., now, and I take my 8-year-old daughter on hikes in the nearby mountains. Sometimes, when we sit on a trailside boulder and listen to the winds soughing in the trees, I can almost pretend that I’ve brought her back to Grindstone, the place I had always assumed I would raise my own family.