Several Congressional High Priority Corridors have been designated as future parts of the Interstate Highway System by the Intermodal Surface Transportation Efficiency Act and amendments.

An alternate proposed terminus is located at the I-5/US 50/Capital City Freeway junction in Sacramento, where the future Interstate(s), after continuing north from Stockton along Route 99, can turn west along the Capital City Freeway, already an Interstate route (unsigned I-305), to connect with I-5, which extends north toward Redding.

[6] The route is to remain roughly parallel to I-5, serving major cities in California I-5 does not, including Fresno and Bakersfield.

[7] On May 20, 2021, Senator Jim Inhofe, of Oklahoma, introduced legislation to designate the portion of US 412 between I-35 in Noble County and I-49 in Springdale, Arkansas as future Interstate 42 (I-42).

The senators' stated reasons for seeking an Interstate designation along US 412 included encouraging economic development, expanding opportunities for employment in the region, making travel safer and shipping easier, attracting new businesses, and better connecting rural and urban communities.

Other supporters of the measure include Mayor G. T. Bynum of Tulsa, and the heads of both ODOT and the Arkansas Department of Transportation (ArDOT).

[15] The Michigan State Highway Department officially requested switching the I-67 designation to a route from Benton Harbor to Grand Rapids in 1958, and in the process proposed the northerly extension of the original I-69 from the I-80/I-90/Indiana Toll Road to Lansing.

It would use the Natcher Bridge to cross the Ohio River, Kentucky's I-165 and Indiana's Lincoln Parkway, an expressway facility that would need to be fully upgraded to Interstate standards.

[18] As originally proposed by the Michigan State Highway Department in 1957, I-94 from Benton Harbor to Detroit would have been numbered Interstate 92.

[21] Current backers of the highway propose an east–west axis through northern and central Maine, with three potential freeway links with Canada—two from Québec, and one from New Brunswick.

One portion of the new highway would run from Interstate 395 in Brewer, Maine, to the Canadian border near Calais, with a direct link to New Brunswick Route 1, a major transportation corridor serving the Maritimes.

A second would travel northwest from Interstate 95 near Waterville, Maine, to the Canadian border at Coburn Gore, with a connection to a proposed extension of Quebec Autoroute 10 toward Montreal.

A third would travel due west from I-95 near Waterville, following the U.S. Route 2 corridor through Maine, New Hampshire, Vermont, and northern New York, with Quebec's Autoroute 73 having a southeasterly oriented southern end that heads for the Armstrong-Jackman Border Crossing, as Quebec Route 173 already reaches the United States at the same port of entry.

[24] The Northern Corridor Transportation Group (NCTG) was formed in December 2008 as a means of refocusing the fifty-year discussion on the project.

Senator Kirsten Gillibrand to direct $800 million toward the project as part of the reauthorization of a federal highway transportation bill.

In a historic move, the six northern legislators representing the North Country in the New York State Legislature (Senators Aubertine, Griffo and Little and Assembly Members Scozzafava, Russell and Duprey) signed an official letter of request to the same end.

In 2006, the Virginia General Assembly directed the Secretary of Transportation to initiate a study to determine the interest of affected states in the construction of a new Interstate highway (I-99).

This would be separate from the existing Interstate 99 in New York and Pennsylvania, and unlike the current route, would fall into its place on the numbering grid.

I-274 first appeared on North Carolina Department of Transportation (NCDOT) planning maps in the early 2000s but was later disused for over a decade since.

On May 20, 2019, the American Association of State Highway and Transportation Officials (AASHTO) approved a request to establish Future I-274.

Justification given by NCDOT was that the 16.83-mile (27.09 km) section would satisfy a great need to alleviate congestion in Winston-Salem and connect the western portion of the urbanized area.

From there, it will continue northward to an extension of Illinois Route 390 (IL 390, formerly known as the Elgin-O'Hare Expressway) and I-90 (Jane Addams Memorial Tollway).