Interstate 42 (I-42) is a partially completed Interstate Highway in the US state of North Carolina, currently existing in two separate segments in the eastern part of the state, totaling . The completed and signed segments of I-42 currently run from I-40 eastwards along the Clayton Bypass to an interchange with Business US 70 southeast of Clayton. The Interstate resumes again along the Goldsboro Bypass, running for north of Goldsboro, ending again at US 70. The Interstate eventually will run from I-40 to Morehead City, where it will terminate along the Northern Carteret Bypass, north of Beaufort. I-42 also overlaps the Clayton Bypass Scenic Byway, from I-40 to US 70 Bus.

Route description The Clayton Bypass is a four-lane freeway that is in length south of Clayton. Starting west of Clayton at a turbine interchange with I-40 and NC 540 on the Wake–Johnston county line, it continues southeast and has a 3-mile concurrency with NC 36, before reaching an interchange with US 70/US 70 Bus., where US 70 merges into the through traffic. Mile markers along the route are based on I-42 and the speed limit is throughout.

The Goldsboro Bypass is a four-lane freeway that is in length north of Goldsboro, connecting with US 70 at both ends. Starting west of Goldsboro, it splits off from US 70, which continues on towards Goldsboro. In a northeasterly direction, it connects with NC 581, I-795 and US 117, where it turns southeasterly. After connecting with Wayne Memorial Drive, US 13, and Parkstown Road, it merges back as the through traffic with US 70 near La Grange. Mile markers along the route are based on I-42 and the speed limit is throughout. The bypass serves both as a strategic transportation corridor for North Carolina and part of the Strategic Highway Network (STRAHNET).

History A multi-county project, also known as the "US 70 Corridor" or "Super 70", is a collection of several projects along US 70 to improve passenger and freight movement eventually leading to the establishment of Interstate 42 (I-42), which is the US Department of Transportation's High Priority Corridor #82 from the Intermodal Surface Transportation Efficiency Act (ISTEA) of 1991. The Fixing America's Surface Transportation Act (FAST Act), signed by then President Barack Obama on December 14, 2015, added the US 70 corridor between Garner and Morehead City to the Interstate system as a future Interstate. Justification for the designation included better connections with Seymour Johnson Air Force Base, the North Carolina Global Transpark, Marine Corps Air Station Cherry Point, and the Port of Morehead City with the rest of state and the eastern seaboard. With no specified number codified in the act, the Regional Transportation Alliance (RTA) expected this corridor to be designated Interstate 46 (I-46) or another suitable designation, and the US Highway 70 Corridor Commission recommended Interstate 50 (I-50). On March 30, 2016, Governor Pat McCrory and various officials unveiled "Future Interstate" signage along the corridor.

For the spring 2016 AASHTO Special Committee on U.S. Route Numbering, NCDOT proposed Interstate 36 (I-36) for this route since there were no other routes with that number in the state. However, on May 24, 2016, AASHTO assigned Interstate 42 for the route. The entire project has a budgeted cost (as of late 2018) of about $1.3 billion, and about 29 miles still without a budget. Some projects like the Clayton and Goldsboro bypasses are completed, while others have yet to be scheduled.

In October 2021, AASHTO approved two segments of I-42, the Clayton Bypass and the Goldsboro Bypass; this was followed by the Federal Highway Administration subsequent approval in March 2022. In May 2022, AASHTO also approved the elimination of US 70 Bypass, clearing the way for NCDOT to fully redesignate the route. Signage for the route was expected to be put up later in 2022, but took a few years to take place, with signage going up in the later part of 2024. In July 2023, NCDOT announced that they were proposing to renumber NC 42 to NC 36 (which was the number originally suggested for the new interstate before 42 was chosen) between NC 50 and U.S. Route 70 Business (US 70 Bus) in Clayton in order to avoid confusing motorist when the Clayton bypass is designated as I-42. Once I-42 is fully completed on the Clayton Bypass and the project with nearby NC 540 is completed, US 70 will be rerouted onto its old routing through Clayton, which is currently designated as US 70 Bus. NCDOT requested public input on this proposal at an open house on October 12, 2023. US 70 has also been upgraded to interstate highway standards between Dover and New Bern, but this cannot be signed as I-42 until the Kinston Bypass is completed as this segment is not connected to the Interstate highway system. I-42 signage began being installed on September 16, 2024, on the Goldsboro Bypass, marking its establishment. Additionally, signage for I-42 has been installed on overhead signs at its western terminus, with the signing of the Clayton Bypass itself completed in 2025. I-42 is expected to be completed in its entirety by 2032 and will include the installation of broadband fiber along the entire route.

Clayton Bypass On June 9, 2008, the Clayton Bypass opened, redirecting US 70 onto I-40 between exits 306 to 309 and then on a new four-lane freeway bypass south of Clayton. Planning for the bypass began in 1991, but construction did not start until 2005 because of several delays regarding the dwarf wedgemussel, an endangered species, habitat in the area. Originally scheduled for completion in June 2009, a severe drought in 2007–2008 allowed construction to proceed more rapidly than anticipated. NCDOT was given the approval by AASHTO to officially designate US 70 along the bypass on May 6, 2008, with the former alignment becoming an extension of US 70 Bus. Compared to the former alignment through Clayton, the bypass is estimated to cut fifteen minutes of travel time for drivers traveling between Raleigh and eastern North Carolina.

In November 2023, AASHTO approved the eliminating part of US 70 Bus., between Garner and Clayton, and rerouted mainline US 70 off the Clayton Bypass and back along its former alignment through there. I-42 had been designated on the Clayton Bypass in 2022, although it was not fully signed as such until 2025.

Goldsboro Bypass

Construction started on the central section of the Goldsboro Bypass on October 9, 2008; its contract was awarded to Barnhill Contracting Co. of Tarboro. At a cost of $65.5 million (equivalent to $ in ), it features three interchanges connecting I-795, US 117 and Wayne Memorial Drive (SR 1556). On December 16, 2011, the central section became the first segment of the Goldsboro Bypass to open; signed as NC 44.

In 2012, both eastern and western sections of the bypass began construction. The eastern section's contract was awarded to Barnhill Contracting Co. in February, at a cost of $104.4 million (equivalent to $ in ). The western section's contract was awarded to S.T. Wooten in July, at a cost of $62.4 million (equivalent to $ in ). On September 25, 2015, the American Association of State Highway and Transportation Officials (AASHTO) approved the establishment of US 70 Byp., dependent on the completion of the Goldsboro Bypass. On October 17, 2015, the western section became the second segment to open; connecting US 70 and I-795, with an interchange at NC 581.

The eastern or last section of the Goldsboro Bypass was opened on May 27, 2016; from Wayne Memorial Drive (SR 1556) to US 70, with interchanges at US 13 and Parkstown Road (SR 1714). The section opened with a ribbon cutting ceremony and all signage that formally delineate NC 44 would be changed to US 70 Byp. after the event.

On June 5, 2021, a section was dedicated to former Goldsboro Mayor Chuck Allen.

In May 2022, US 70 Bypass was replaced by I-42; I-42 signage replaced US 70 Bypass signage in fall 2024.

Future Wilson's Mills improvements

A section of US 70 at Wilson's Mills, connecting to the Clayton Bypass in the west will be upgraded to a freeway for an estimated $31 million. The plan calls for US 70 to be carried on a bridge over Wilson Mills Road while a bridge will carry Swift Creek Road over US 70. Interchanges will be made at both roads and a connector road paralleling US 70 between the two roads will also be built. Construction was planned to begin in 2020 and finish around 2022. However, COVID-19 funding issues postponed the awarding of the construction contract from September 2020 to March 2021. Construction officially began on May 12, 2021, and was expected to be completed by the middle of fall 2024. The Swift Creek Road exit was partially opened to traffic in spring 2024. After some further delays due to drainage issues along the segment, the project was officially completed on December 17, 2025, after all the "Speed Limit 70" signs were added. I-42 signage will be added once it is approved by the FHWA.

Smithfield/Selma improvements Improvements are in the planning stages for the segment of US 70 between Wilson's Mills and Princeton. Some of this section is already a freeway but will require improvements to bring it up to interstate standards and add an interchange with I-95. Adding the interchange will require shifting I-95, which is going to be widened in this area, east to incorporate the new changes. This proposed project is still in the study phase and not currently budgeted nor does it have a timeline for completion. I-95 and US 70 Business Route (exit 95) is being reconstructed though.

Princeton Bypass to Goldsboro Bypass The existing Princeton Bypass eastward to the Goldsboro Bypass will be improved to interstate standards, which is estimated to cost $170 million. The project for the upgrade of US 70 will be done in two parts: the first will be in the Princeton area between US 70A to North Pearl Street/Edwards Roads (construction is scheduled to start in 2025) with second part starting there and ending at the Goldsboro Bypass (construction is scheduled to start in 2028). Currently, project funding has been suspended by NCDOT due to the agency's budget issues. The agency is currently working with state legislators to find alternative sources of revenue.

Kinston Bypass