Northwest Passage Scenic Byway – All American Road

Iron Horses at the Entrance to Lewiston Photo: Digital Barn Iron Horses at the Entrance to Lewiston

In 1803, President Jefferson commissioned Meriwether Lewis and William Clark to find the Northwest Passage – the link between the Missouri River and the Columbia River through the unexplored Rocky Mountains. This 202-mile byway, stretching across North Central Idaho, follows the explorers' route through the ancestral homeland of the Nez Perce people.

From the west, this beautiful route begins on U.S. 12 at Lewiston, and traverses the winding Clearwater River Canyon, passing through the Nez Perce National Historical Park areas of Spalding and Kamiah and the towns of Orofino and Kooskia. At Kamiah is the Heart of the Monster, a geologic formation and legendary Nez Perce site.

At Kooskia the byway splits. One segment turns south on Idaho Highway 13 toward the Camas Prairie and the town of Grangeville. Another segment continues east on U.S. 12 along the Middle Fork of the Clearwater River, and the Lochsa Wild and Scenic River, through a magnificent wilderness culminating at the Lolo Pass Visitor Center.


Begins in Lewiston and follows U.S. 12 northeast to the Idaho–Montana border; also follows Idaho 13 from Kooskia to Grangeville and the junction of U.S. 95.


202 miles. Lewiston to Montana, 175.5 miles, allow 4 hours. Kooskia to Grangeville, 27 miles, allow 40 minutes.


Idaho 13 and U.S. 12 above Kooskia are winding, two-lane roads with occasional passing lanes and slow vehicle turnouts. Winter driving conditions may include black ice in the canyons and snow-covered roads at higher elevations.


Full services in Lewiston, Orofino, Kamiah, Kooskia, Grangeville.  Last services available in Lowell.

About Us

Corridor Management Plan

Contact Info

Lewis Clark Valley Chamber
North Central Idaho Travel Association
Nez Perce National Historical Park & Museum
Nez Perce Tribe
Clearwater National Forest
Nez Perce National Forest
Lewis Clark National  Historic Trail
Nez Perce National Historic Trail