AR 18/AR 91 run together with US 63 into Jonesboro. AR 18 breaks and runs as Highland Dr., meeting US 49/AR 1. Then later, it meets US 78 where it begins concurrency with. After Jonesboro, US 78/AR 18 meets AR 158 and AR 135 in Lake City. The four routes continue east to Black Oak, when US 78/AR 18 turns north. US 78/AR 18 briefly runs with AR 139 in Monette before continuing east. AR 18B is created in Manila, and US 78/AR 18 meets AR 77.
Highway 18 was created during the 1926 Arkansas state highway numbering from Diaz to Barfield similar to the present-day alignment.[1] The designation was shifted onto Nettleton Cut-Off Road in Jonesboro on March 9, 1955.[6] The highway was rerouted between Leachville and Manilla on July 10, 1957, with Highway 18 taking over the former alignment of Highway 18 Spur.[7] It was extended to Barfield Landing on April 24, 1963, as part of a major expansion of the state highway system.[8] The western terminus was extended west to Highway 69 in Jacksonport on November 23, 1966.[9]
^ abArkansas State Highway Department (April 1, 1926). State of Arkansas Showing System of State Highways(TIF) (Map). 1:500,000. Little Rock: Arkansas State Highway Commission. Retrieved December 23, 2017 – via Arkansas GIS Office.