Despite long stretches of parallel and concurrent Interstate Highways, it has not been decommissioned unlike other long-haul routes such as US 66.

Much of the historic Lincoln Highway, the first road across the U.S. (from New York City to San Francisco), became part of US 30; it is still known by that name in many areas.

The western terminus of US 30 is at an intersection with US 101 at the southern end of the Astoria–Megler Bridge in downtown Astoria, Oregon, approximately five miles (8.0 km) from the Pacific Ocean.

There, it exits and heads east and southeast into Wyoming, not paralleling an Interstate Highway for the first time since Portland.

East of Grand Island, US 30 diverges from I‑80 and runs northeast toward Columbus on a highway parallel to the Platte River.

The majority of`US 30 east of Ames and west of the Mount Vernon–Cedar Rapids area (138 miles [222 km]) is a rural four-lane divided highway.

They both began in Nebraska, entered Iowa in Council Bluffs, and extended north to Missouri Valley via Crescent to meet the current highway.

At Aurora, it turns southeast to Joliet, where it is a major thoroughfare in the city of Joliet (Plainfield Road), and then back east through New Lenox, Frankfort, Mokena, Matteson, Olympia Fields, Park Forest, Chicago Heights, Ford Heights, and Lynwood to the Indiana state line, bypassing Chicago to the south.

This is especially pronounced near Warsaw and Columbia City, where the speed limit is reduced as the highway runs through a commercial section with many businesses and traffic signals.

[12] As of 2020[update], the only sections that were limited access freeways are in Van Wert, Bucyrus, Mansfield, Wooster, and Canton.

After cutting through the town of Chester with only one interchange, West Virginia Route 2 (Carolina Avenue), the freeway section ends not too long after.

US 30 then briefly joins I‑76 near Center City, Philadelphia, splitting onto I-676 as it crosses the Delaware River on the Benjamin Franklin Bridge.

What is now US 30 through those states (west of Burley, Idaho) had been designated as part of US 20, another transcontinental route, but traveled through Yellowstone National Park and was inaccessible during the winter season.

A compromise was reached, in which the US 630 route would become the main line of US 30, once improved to higher standards, but that was still not deemed completely satisfactory.

In the final plan (dated November 11, 1926), the route toward Salt Lake City became US 530, ending at US 40 at Kimball Junction, Utah.

[citation needed] US 30 was rerouted c. 1931 to bypass Omaha, Nebraska, and Council Bluffs, Iowa, to the north.

[citation needed] Later sections were relocated to parallel Interstate Highways in several states, including I-84 in Oregon and Idaho.

[citation needed] In 1988, Pennsylvania Department of Transportation (PennDOT) engineers proposed that US 30 be rerouted and upgraded to a four-lane controlled-access expressway through a portion of Lancaster County.