Salmon River Canyon

The date has moved since the sign was cast. The Idaho Geological Survey now puts the start of the ancestral Salmon River's cutting at about twelve million years ago, cutting down through the basalt flows that cap the uplands here. Those flows came from the Columbia River Basalt eruptions, fed by the plume now under Yellowstone. The canyon the Salmon cut is counted as the second-deepest gorge on the continent, after Hells Canyon of the Snake just to the west.

What the plaque says

Salmon River Canyon Some 15 million years ago, Salmon River ran across great Miocene lava flows above here and started to carve this deep canyon. Then this part of the earth's surface gradually rose. As the mountains were rising, the river cut down into the older rock below. Many other northwestern rivers cut similar gorges. The Snake flows through Hell's Canyon--deepest of them all--8 miles west of here. 313

Where it stands

Worth the stop nearby

• White Bird Battlefield — 12 mi
  Six Nimiipuu men rode out under a white flag. A shot came from the soldiers' side, and the Nez Perce War began.
• Heaven's Gate Lookout — 20 mi
  A staffed fire lookout at 8,429 feet on the rim of North America's deepest river gorge, nearly reachable by car.

More markers nearby

• Fabulous Florence — 4.7 mi
• Hydraulic Mining — 4.7 mi
• Nez Perce War — 13 mi
• White Bird Grade — 13 mi