The national road and highway system in America used to be a mess of misconnected patchwork roads until things started to really improve through the Federal-Aid Highway Act of 1956. Now with common standards the highway system covers highways and roads that crossover and connect all over the united states. There are dozens of different ways you could travel from one end of the U.S. to the other.
Have you ever done a big road trip where it feels like the same road just goes on and on and on? The longest highway in the country is not part of the major interstate system. However it still runs through 12 states, including Idaho. According to 24 hour wall street U.S. Rout 20 is part of the older naming convention of U.S. highways. U.S. Route 20 stretches 3,365 miles, making it the longest highway in the country.
According to the Department of Transportation, The route begins in Boston at a junction with Massachusetts Route 2 and ends in Newport, Oregon, at a junction with U.S. 101. Because U.S. numbered highways are not designated with National Parks, U.S. 20 is divided into an East Section ending at the eastern entrance to Yellowstone National Park and a West Section beginning at the west entrance to the park.
The states it runs through are Oregon, Idaho, Montana, Wyoming, Nebraska, Iowa, Illinois, Indiana, Ohio, Pennsylvania, New York and Massachusetts. These states are responsible for maintaining and repairing the road that is within their state boundaries.
According to Wikipedia, Since 2019, US-20 has been designated as the Idaho Medal of Honor Highway. US 20 crosses into Idaho northwest of Parma, running concurrently with US 26 and joins US 95 through Parma. US 20/US 26 leaves US 95 southeast of Parma and runs to Caldwell where US 20/US 26 joins with I-84 and US 30 for a short time. These four highways parallel each other (on two roadways) to Boise where US 20/US 26 runs through downtown before joining with I-84 and US 30 again to Mountain Home, where it departs at exit 95 to head east, past Rattlesnake Station, Anderson Ranch Dam road, and cresting at Cat Creek summit at 5,527 feet (1,685 m) above mean sea level. It continues into and across Camas County through Fairfield to Timmerman Junction, the intersection in Blaine County with State Highway 75, the route to Sun Valley, Galena Summit, and Stanley. US 20 continues east through Picabo and Carey, joined with US 26 and US 93, to Craters of the Moon and Arco, where US 93 splits off and turns north-northwest to climb the Big Lost River valley. US 20/US 26 continues on through the Idaho National Laboratory, where the highways split just west of Atomic City; US 26 heads to Blackfoot and US 20 to Idaho Falls, where it turns north-northeast to pass near Rexburg as a freeway. US 20 then climbs through the communities of St. Anthony, Ashton, and Island Park, and crosses the Continental Divide at Targhee Pass at 7,072 feet (2,156 m), entering Montana west of West Yellowstone.