From Washington State at the city of Newport, the Northern Tier Routes (NTR) travels east on US highway 2 and crosses the Pend Oreille River, (a tributary of the Columbia) on the Thompson Memorial bridge. Then, the NTR continues upstream along the north side of this river further into the Idaho northern panhandle, passing trough Priest River, Idaho and continues eastward to Dover where it Pend Oreille River flows out of Lake Pend Oreille, a natural lake formed by glacial action. Lake Pend Oreille is the largest lake in Idaho with a surface area of 148 square miles. Sandpoint, Idaho where US 2 joins with US 95 and continue through Ponderay Idaho. Then, the NTR continues northbound on US 2/US 95 to Bonners Ferry, Idaho, and when leaving Bonners Ferry, the US highway crosses over the Kootenai River Bridge, after which climbs for a time providing backward views of Bonners Ferry.

Then, at Threemile Corner, Idaho, the two US highways split, US 95 continues north to the Canadian border crossing, while US 2 and the NTR turns east towards Montana. In about five miles the NTR arrives in Moyie Springs, Idaho and then the highway turns to the southeast and soon arrives at the Moyie River, a tributary of the Kootenai River, which is a tributary of the Columbia River that flows partially as the border between the states of Washington and Oregon. After crossing on the concrete deck Moyie River Canyon Bridge, there is a put out on the right immediately afterwards. This is a nice overlook looking back to the river corssing and there is also two signs providing information about both the canyon and the bridge.

The US highway 2 extends from the Washington state line in Newport, Washington just before crossing the Thompson Memorial Bridge over the Pend Oreille River and traverses the top of Idaho eastbound to the Montana state line near the town of Moyie Springs, Idaho. This stretch of the US highway was constructed in 1925 as part of the original U. S. highway system with the original western terminus at Bonners Ferry, Idaho. In 1946, US 2 was continued westbound through Idaho to the state border of Washington, at which time the construction was extended west to Everett, Washington.

The Moyie River Canyon Bridge is the current US 2 bridge over the Moyie River, which is a structural steel truss cantilever bridge that spans the Moyie River in the city of Moyie Springs just east of Bonners Ferry, Idaho. The bridge at 1,223 feet (373 meters) long and 464 feet (141 meters) high was constructed in 1965 at mile marker 70 on US 2, and is a replacement for an obsolete 1923 bridge built downstream of the Moyie River Dam.