| State: | AR |
| Type: | AR |
| Route: | 18 |
| Map: | Arkansas 18.png |
| Formed: | 1926[1] |
| Length Mi1: | 0.93 |
| Length Ref1: | [2] [3] [4] [5] |
| Direction A1: | West |
| Direction B1: | East |
| Length Mi2: | 92.83 |
| Length Ref2: | [6] [7] [8] [9] |
| Direction A2: | West |
| Terminus A2: | in Diaz |
| Junction2: |
|
| Direction B2: | East |
| Previous Type: | AR |
| Previous Route: | 17 |
| Next Type: | AR |
| Next Route: | 19 |
Arkansas Highway 18 (AR 18) is a designation for two state highways in northeast Arkansas. One segment of 0.93miles runs from Highway 69 east of Jacksonport east to Highway 17 in Diaz. A second segment of 92.83miles runs from Highway 17 in Diaz east to the Mississippi River.
Highway 18 begins at Highway 69 east of Jacksonport and heads north for 0.93miles until it reaches the intersection of Highway 17 in Diaz, where it terminates.
The route begins at Highway 17 in Diaz and runs east, before meeting I-57/US 67 in Newport. Highway 18 continues east to Highway 37 in Grubbs before turning north at Uno to Highway 226 in Cash. The route joins Highway 91 and becomes King's Highway.
Highway 18/Highway 91 run together with US 63 into Jonesboro. Highway 18 breaks and runs as Highland Drive, meeting US 49/Highway 1. Then later, it meets US 78 where it begins concurrency with. After Jonesboro, US 78/Highway 18 meets Highway 158 and Highway 135 in Lake City. The four routes continue east to Black Oak, when US 78/Highway 18 turns north. US 78/Highway 18 meets Highway 139 in Monette before continuing east. Highway 18B is created in Manila, and US 78/Highway 18 meets Highway 77.
Both routes briefly meets Highway 181 near Dell before turning northeast to Blytheville. US 78/Highway 18 meet Highway 151 and US 61 in downtown Blytheville. The route continues east to cross over I-55 (exit 67) in a frontage road interchange where US 78 departs from the highway to enter I-55. Highway 18 and Highway 312 meet briefly south of the Blytheville Municipal Airport. The route continues east to terminate at the Mississippi River.
Mile markers reset at some concurrencies.}}
Highway 18 was created during the 1926 Arkansas state highway numbering from Diaz to Barfield similar to the present-day alignment. The designation was shifted onto Nettleton Cut-Off Road in Jonesboro on March 9, 1955.[10] The highway was rerouted between Leachville and Manilla on July 10, 1957, with Highway 18 taking over the former alignment of Highway 18S.[11] It was extended to the Mississippi River on April 24, 1963, as part of a major expansion of the state highway system.[12]
See main article: Auxiliary routes of Arkansas Highway 18.