On a brisk October morning, people gather in the pre-dawn hours as the sky begins to brighten. Wearing heavy jackets and bundled tight with blankets, they struggle against cold, windy weather that makes it feel more like winter than fall.

Spreading out across a rocky mountaintop, they take part in the tradition that is observing the sunrise in Maine’s vast Acadia National Park.

Its 47,000 acres, with their sharply hewn coastline and pristine woods, take up much of Mount Desert Island, and those who make the pilgrimage up Cadillac Mountain — the highest point on America’s Eastern Seaboard — are some of the first in the United States to see the sun peek over the horizon.