From Junction View the ground simply falls away. Highway 180 tips over the rim of the South Fork of the Kings River and begins one of the great descents in the American West, dropping well over a thousand metres in a long series of ledges and bends cut into the canyon wall. Below you the river is a thin white thread, and across the gorge the slopes rise in grey and rust-coloured rock to peaks that hold snow into summer. Kings Canyon is among the deepest canyons in North America, deeper in places than the Grand Canyon, though it hides it well behind its curves.
This is the bit to savour. The road was blasted into the cliffs in the decades before it opened to Cedar Grove in 1939, and in places it hangs on the wall with nothing but a low stone barrier between you and a long drop. The corners are smooth and well cambered, more fast-flowing than tight, but they come in long sequences and the heat bouncing off the rock can be fierce by early afternoon. Rockfall is a real thing here, especially after rain, so keep scanning the inside line for debris.
Halfway down, at river level, the canyon narrows between marble walls and you pass Boyden Cavern, a marble cave that runs tours in summer. The air down here smells of warm granite and river spray, and the South Fork roars through a slot of polished rock. A little further on, Grizzly Falls drops right beside the road, close enough to cool your face on a hot day.
John Muir thought this valley a rival to Yosemite, and he fought for decades to protect it from dams. The national park was created in 1940, but the canyon floor around Cedar Grove was only added in 1965, after the dam schemes were finally buried, and that is a large part of why it still feels so wild. The road sees a fraction of Yosemite's traffic, and on a weekday in June you may have whole stretches to yourself.
Practicalities are simple and strict. The road beyond the Hume Lake turnoff is closed from mid-autumn until spring, usually from mid-November to late April. Nobody sells fuel in the canyon itself, so arrive with plenty, ideally from the valley towns around Woodlake or Orange Cove, and remember that this is a dead end: everything you ride down, you ride back up.