Lighthouses, lobsters, and always the sea: Portland's Casco Bay archipelago is the twenty-third state distilled to its essence. Jennifer Finney Boylan plies the waters—and unearths the legends—of a stone-cold classic

It is my last day visiting Maine's Casco Bay, and I am looking for the Fountain of Youth, said to be in the mudflats off Cousins Island. Its exact location is unclear, however, and the only people I can find to ask directions of are gathered on a pier, waiting for the Great Chebeague Island ferry. Thus, it is with more than a little embarrassment that I walk up to a group of complete strangers and say, "Excuse me, but I'm looking for the Fountain of Youth?"

After an awkward pause, an older man in a Red Sox cap speaks up. "Aw, I heard that story when I was a kid," he says. "We did use to have one around here somewhere. But then we lost it."

"Here comes Ellen," another man says, nodding toward an intelligent-looking woman walking toward us. "I bet she knows where it is."

Ellen, to my surprise, turns out to be Pulitzer Prize–winning Boston Globe columnist Ellen Goodman, and for a moment I envision us spending the rest of the afternoon together, two women digging in the mud for immortality. But Ellen simply gives me a worried look and says, "I don't know anything about eternal youth." Then adds, "Although I think it's a nice idea."

For a moment we stand on the pier together, looking out at Casco Bay and its archipelago of little green islands, at the ferryboat steaming toward us across the sparkling waters. Then, it's clearly time for me to go, so I thank Ellen and the others and head back to my car, temporarily disappointed.

But as I drive toward the mainland, it occurs to me that if you lived in beautiful Casco Bay, eternal youth would probably be something you'd never miss. You'd awaken each morning to the cries of the gulls and the roar of the ocean and never once feel old or that your days had been misspent.

I'd gotten my first glimpse of the islands from a hot-air balloon three days prior. Although I'd never ridden in a balloon before, it struck me as a pleasantly grandiose way to kick off an exploration of Casco Bay. I met the pilot, Joe Shevenell, at 5:30 a.m. in a parking lot in Portland, and half an hour later we were in a small suburban park, preparing for takeoff. A woman named June, who lives next door to the park, was just finishing her morning jog when the pilot spotted her and said, and I quote, "Would you like to ride in my beautiful balloon?" Five minutes later, Joe and June and I were eleven hundred feet above Portland, enveloped in complete silence and peace, broken only by the occasional fiery blast from the propane burner overhead.

"I can't believe I'm doing this!" said June. "I'm supposed to be at work!"

We'd had a little trouble catching the right air currents, so instead of floating parallel to the bay, heading for a landing in Yarmouth, we were drifting toward the ocean, where presumably we would all wind up in Davy Jones's locker—or, with my luck, in Peter Tork's. While my imminent demise was cause for some consternation, the elevation did give me the chance to see Casco Bay in nearly its entirety, from the largest of its 222 islands—Great Chebeague, almost five miles long—to the Junk of Pork, which is scarcely more than an acre.