Henry Clay Merritt, on His 158th Birthday

June snow falls as a reminder. A reminder that Idaho's high valleys are not an easy place to live, a reminder that killing cold is never far away and that even the most reasonable plans can become stunted, a reminder that summer is a welcome friend who comes dressed in fine clothes for only a short visit, but that you live with winter. In a valley divided by the Salmon River, rain drizzled down, and the temperature hovered just above freezing. In the mountains bordering the valley, I glimpsed traces of white on the ground and imagined peaks then hidden by low clouds, sheeted in snow so wet and heavy it bent and broke tree limbs, crushed and flattened spring wildflowers. The eighth day of my kayak trip to the Pacific Ocean, Monday, June 4, had started as a day to get past and nothing else.

The ocean remained a long way off—750 miles or so if I figured by distance, two months or so if I calculated by time—far enough away that its existence seemed more rumor than certainty, more possibility than reality. I felt all those river miles laid out ahead of me, and all that time and distance weighed on me the same way wet snow weighs down whatever it sticks to. There was nothing to do but keep moving.

I camped for the night under a tall pine. The rain had mostly stopped by then, but the wet lingered, collected at the ends of long ponderosa needles and dropped on the ground, or on me, in heavy splats. A green plastic tarp, weighted with rocks on each corner, covered gear I wanted kept dry. I changed into dry clothes, and it took all of them to keep me warm. My bivy sack and red kayak were next to a picnic table, my camp stove and cooking pots on the table. Dinner was what I could make by boiling water—pasta, ramen noodles, or instant couscous. I didn't care; food boredom had already set in.

After eating I explored the campground, which occupies part of an old homestead settled by Jim and Mamie Hibbs sometime around 1900, after Jim had moved west from Missouri a few years earlier. The Hibbses had raised nine children there. A Forest Service sign dutifully pointed out a hundred-year-old black walnut, a tree not native to the region and obviously planted by the homesteaders. I could imagine the family gathering its nuts for food each fall. If the Forest Service hadn't used the spot as a campground, time already would have erased most signs of the family's life. Wild roses fill irrigation ditches the family must have dug by hand. The pink flowers were in bloom and gave the air a sweet, heavy smell. Johnny Carrey and Cort Conley, in their history of the Salmon River, River of No Return, write about the Hibbses' homestead. It is a story of constant work: of running a water-powered sawmill and then packing or boating the boards to nearby mines, for Jim, of washing clothes for miners (at one point, the area boasted more than three hundred mining claims) and caring for livestock and children and a garden, for Mamie. After thirty years on their homestead, with most mines closed and the people who worked them leaving or gone, the Hibbses, for reasons now lost, called it quits, sold their land to a man who sold it to someone else, who sold it to the government in 1945.

I had paddled all day to reach the campground, although I had decided on no particular stopping point that morning when I left a hotel room in the town of Salmon, some thirty-five miles upstream. I had thought out little beyond the plan to kayak three rivers—the Salmon, Snake, and Columbia—that are, in a way, all the same river. The Salmon feeds into the Snake, the Snake into the Columbia, and the Columbia into the Pacific Ocean.

The Columbia, if judged by discharge, is the fourth-biggest river in North America and...