By the time the tiny hut came into view, nestled high in a corrie in Scotland’s 1,748-square-mile Cairngorms National Park, I’d trekked for nearly nine miles, three of which, regrettably, I’d had to navigate after nightfall. The hike, through a broad valley in the Eastern Highlands called Glen Derry, carried me past groves of Scots pines and over a series of streams, some of which, lined with slick steppingstones, made for precarious crossings. All the while, two rows of smooth, eroded mountain peaks enclosed me in an amphitheater of muted colors: hazel-hued heather, golden grasses. Though much of my walk was solitary, the flickering glow in the hut’s main window, I knew, meant I’d have some company for the night and the warmth of a fire to greet me.

My overnight home, the Hutchison Memorial Hut, colloquially called the Hutchie Hut, which I visited in late October, is one of more than 100 rustic shelters scattered throughout England, Wales and Scotland that are frequented by a motley assortment of outdoor adventurers. Left unlocked, free to use and with most offering little more than a roof, four walls and perhaps a small wood-burning stove, the buildings, called bothies (rhymes with “frothy”), are an indispensable — if for many years underground — element of British hill culture.