Wendell Berry wrote: “If you don’t know where you are, you don’t know who you are.”

If so, then nowhere do I know myself better than when I am on the Vineyard.

If I stand at the corner of South Summer street and Davis Lane, my feet planted firmly at the front door of the building this paper calls home, I know my parents got married one block south and that my brothers were born six miles northwest. I know I was raised in a house four blocks northeast and that my grandparents are buried a mile due south.

I know I learned how to skate on a pond a half-mile to the north, back when the ponds used to stay frozen all winter long, and that I learned how to drive in my grandmother’s 1963 Volkswagen beetle in a sand lot by South Beach.

I was married on a different beach one mile north, and received a breast cancer diagnosis in the same hospital where my brothers were born.

That summer day, in an effort to carve out some time to metabolize the news and plan for what was to be a year of surgeries and treatment, my husband and I double-knotted our shoes and headed out for a run. My father had offered to take care of our children, then three and five. We told him we weren’t sure how long we’d be gone. He nodded in silent assent.

The truth was, we weren’t sure about much. Uncertainty was the terrain we’d be navigating for the foreseeable future and that day we took our first tentative steps onto its unfamiliar surface.

There was so much we didn’t know. We were cartographers with neither compass nor sun: a bit lost and a lot disoriented. In the intervening years I’d come to understand better the dark presence of anticipatory dread. Once the ground gives way under your feet even a single time, you never again step with the blind confidence of the healthy and the undiagnosed. But you still walk. You still run.

Out of the gate our pace was slow. We were direction-less. We wandered north and looped around Starbuck Neck, cut through Sheriff’s Meadow and popped out onto Planting Field Way. While we talked, our feet carried us by force of habit towards Morning Glory Farm, where we picked up the bike path heading west. By the time we got to the airport we’d grown tired of pondering the what if’s and began instead to focus on the what for’s.

For the kids, obviously. I’d fight to stay here for the kids. Our pace quickened. And for my whole family, of course. They were worth the battle. My husband and I kicked it up another notch. And for me. I was just 40. I had a whole second act if I was willing to go to the mat for it. We weren’t talking much now, our sharp exhales matching our increased cadence. Every athlete facing a contest of endurance needs to know her why’s. Mine had just announced themselves.

We called my father from Alley’s and told him to meet us at the Gay Head Light, 21 miles down the road from where we started. When we crested the penultimate rise and the lighthouse hove into view, I could see three figures in the distance — one tall, two small — standing on the side of the road. They were holding a frayed old dinghy painter between them, my father on one side, my children on the other. It was a makeshift finish line. It was a starting line, too.

I’ve returned to the Island every year since from our home in Cambridge to run from lighthouse to lighthouse. Some years I’ve run east to west, like that first year, trading the bobble-headed hydrangea of Edgartown for the windswept miscanthus up-Island. Other years I’ve run west to east, putting the significant hills behind me by halfway and ratcheting down the pace on the shady pin-straight paths through the state forest.

We’ve made the trek in the summer and in the winter, one year with a January tailwind so fierce I thought for sure my rear end was frostbitten by the time we reached the top of North Water street.

My husband has joined me for every iteration, either on foot or on bike. My stepdaughter, my first and best marathon training partner, ran the distance with me one year while her husband cycled. A few friends have jumped in for segments here and there. More recently my children started biking it with us. They pedal alongside me, blasting Taylor Swift and proffering jelly beans from their damp pockets. They tell me I’m doing great.

I know I’m doing great. I’m doing great because I’m still here. Still gulping for oxygen late in the run, and still feeling the steady Morse code of my heart knock its familiar message. But also still here, on this Island, my feet carrying me east and west and east again, a bipedal pendulum marking the years one cross-Island journey at a time. Still here. Another year. Still here.

I turn 50 on July 1. I’ve invited a few friends and family to meet me at the lighthouse in Gay Head that morning. We’ll run, walk or bike the distance from one end of the Island to the other. My kids will deejay. My Dad will hold the finish line. If you see us out on the road, give a wave. We’ll almost certainly wave back.

Better yet, roll a few miles with us. Whose day can’t be made slightly better by a little collective high-heart-rate work?

Whether I’m feeling sluggish or spry, logging a handful of morning miles never fails to tell me how I’m doing. Logging those miles on the familiar roads of the Vineyard, with friends and family near at-hand, will never fail to tell me who I am.

Amory Rowe lives in Cambridge.