The designation was approved in 1997 at the request of a coalition of counties in North Carolina and Virginia who saw it as a way of further developing that area's economy. Most of the route will use existing US 29 north of Greensboro; however, for a few miles I-785 will run between US 29 and its parent route,
I-85 on the
Greensboro Urban Loop, which will also carry the I-840 designation. Construction of this highway was due to begin in 2011. With the upgrade of the
Danville Expressway to a four-lane route in 2004, the I-785 route in
Virginia is complete (and has been given the interim designation SR 785), but US 29 still needs to be upgraded to
Interstate standards in North Carolina between the Greensboro Loop and
Reidsville before the route can be signed as an Interstate. At that time, there were no projects scheduled by NCDOT to do so. Given that in the spring of 2006 NCDOT put up mileposts and added numbers to exit signs from Reidsville to the Virginia border reflecting US 29's mileage, an upgrade of this highway to an Interstate apparently was not in their immediate plans. On July 31, 2013, NCDOT got approval from the
Federal Highway Administration (FHWA) to cosign the first section of I-785 with I-840 in eastern Guilford County officially establishing I-785 in North Carolina. The next section of I-785 opened on December 6, 2017, with hidden concurrency of I-840. With an estimated cost of $119 million (equivalent to $ in ), the section, completing the eastern segment of the Greensboro Urban Loop, goes from US 70 (Burlington Road) to US 29, with an interchange at Huffine Mill Road. On September 13, 2019, a Reidsville Transportation Forum was held where it was announced I-785 is now funded and committed by NCDOT from its current ending point at exit 14 to US 29/US 158 exit 153 at the northernmost Reidsville city limits. Many officials from the
North Carolina General Assembly and NCDOT presented at the forum, with the Reidsville Chamber of Commerce sharing quotes from these officials afterward regarding I-785. The construction of I-785 being extended to the city of Reidsville is a reflection of the city's growth as a center of transportation and commerce in the north Greensboro metropolitan area connecting with the Reidsville US 158 corridor. ==Future==