High Quality Content by WIKIPEDIA articles! Interstate 73 (abbreviated I-73) is a main route of the Interstate Highway System, currently located entirely within the U.S. state of North Carolina. It is part of a longer planned corridor, defined by various Federal laws to run from Myrtle Beach, South Carolina, to Grayling, Michigan, but only the part south of West Virginia is currently under study. Closely related is the extension of Interstate 74 from Cincinnati, Ohio to Myrtle Beach, with several concurrencies planned.