The remote and rugged Klamath River in Oregon and California, one of the mightiest in the American West and an ancient lifeline to Indigenous tribes, is running free again, mostly, for the first time in 100 years after the recent removal of four major dams.

At the burbling aquifer near Chiloquin, Ore., that is considered the headwaters, a sacred spot for native people, a group of kayakers, mostly Indigenous youth from the river’s vast basin began to paddle on Thursday. Ages 13 to 20, they had learned to kayak for this moment.

Stroke by stroke, mile by mile, day by day, they plan to reach the salty water of the rugged Northern California coast, more than 300 miles away, in mid-July.

If all goes as planned, the kayakers will pass the rehabilitated sites of the largest dam-removal project in U.S. history. They will pass salmon swimming upstream in places that the fish had not been able to reach since the early 1900s. They will pass through the ancient territory of their tribes — the Klamath, Shasta, Karuk, Hoopa Valley and Yurok among them.