The letter writers come to give thanks, to grieve, and to confess. To leave their most private thoughts, and to read what others have written, in this most public of places: a mailbox, a mile and a half down the beach from the town of Sunset Beach, flanked by two benches and tucked away in a sandy alcove. The address on the mailbox is spelled out in black-and-silver stick-on letters: KINDRED SPIRIT.

It is a shrine, an open secret, an outdoor confessional, on Bird Island.

• • •

On a Saturday, I make the trek with Jill, my wife, to read the messages in the mailbox. And I know that by the time I leave, I will also write my own message, though I haven’t a clue what it will say. The sea is sun-sparkled and flat, the breeze fitful. I expected the remote beach to be deserted, but we pass dozens of walkers and bikers, many in pairs. All along the beach, we find broken sand dollars, never a whole one.

At the southern boundary of Bird Island, behind a rock jetty, a small cruise ship makes its way out of Little River Inlet, moving slowly across our field of vision. Twenty minutes of easy walking brings us to the mailbox. The red flag is up — there’s mail inside. For 35 years or so — since the mailbox was planted in the sand by a woman who wished to remain anonymous — there’s always been mail inside. Stuffed into the mailbox are five notebooks of various sizes, nine pens, and a blue flyswatter.

I sit on a bench and read.

One writer after another offers thanks for a good life, for a beloved spouse, for the gift of being in such a beautiful, tranquil place. The word “blessing” comes up a lot. But there are harder messages to read, too — elegies to husbands and wives, parents and children, who have passed away. Most are seeking hope, some through confession.

One writes of coming here to heal: “I used to have hope. I used to walk in the light and avoid the shadows. … I’m living with regret. I will make a change. Not today, not tomorrow, but soon.”

A little boy prints in an uneven, penciled hand that his great-grandpa has died. “I’m not here for me,” he writes. “I’m here for grandma. She took it especially hard. I completely understand she lost her dad. Then again, I don’t understand because I never knew my dad.” He finishes, “If you really do have connections, Kindred Spirit, tell my true father in heaven to smile upon my grandmother.”

A miniature marbled composition book holds just one triumphant entry: “After 6 mos of walking this beach finally found a whole sanddollar. Whoopi!”

• • •

All at once, we are alone in the alcove, the beach deserted all the way to the breaking waves. The remote, unpeopled place itself inspires candor.

Caught in the moment, I write a note of gratitude to Jill, for the two children she brought to my life nearly a decade ago. Thinking of them reminds me of my parents, both gone now. And of my best friend, whose light plane fell into an Illinois cornfield more than 25 years ago. I am old enough now that there are too many others on that list.

Then I pause and listen, just let the place wash over me: the flat, now-deserted beach, the waves curling gently onto the dark sand. I write, “In the rushing surf I hear the voices of all the ones I have lost, and it brings me peace.”

The cruise ship steams across the horizon, growing smaller as it angles east, till it is hull-down a long way offshore, carrying other kindred spirits out to sea.

From the public beach access to West 40th Street in Sunset Beach, walk or bike southwest, away from the pier. The Kindred Spirit mailbox is about 1.5 miles down the beach; if you reach the jetty, you’ve gone too far. Learn more at thekindredspirit.net.