Entering Arkansas County, the routes pass through Gillett and rural Arkansas County. In south De Witt AR 1 splits east from US 165 and AR 1 Business. AR 1 bypasses southeast De Witt, and after reconnecting with AR 1B continues northeast. AR 1 runs east through St. Charles before entering Monroe County. AR 1 Spur enters St. Charles, and terminates near the site of the Battle of Saint Charles on the White River. Arkansas Highway 1 enters southern Monroe County briefly. At Cross Roads, AR 1 is the southern terminus of AR 17. On the Monroe/Phillips County line, AR 1 has a junction with Arkansas Highway 39 and Arkansas Highway 316. The route continues northeast to Marvell, where AR 1 concurs with U.S. Route 49 east to Walnut Corner. At the corner, AR 1 turns north past the Richardson-Turner House and enters Lee County. The route has a junction with AR 121 at Cypress Corner and continues north to Marianna. In Marianna, Highway 1 breaks west from AR 1 Business, which runs downtown through Marianna. After AR 1B rejoins the main route, there is a concurrency north with U.S. Route 79. Further north, AR 1 passes Lee County Senior High and becomes four lane briefly until Forrest City. Upon entering St. Francis County, AR 1 enters Forrest City. The business route runs downtown, while the main route skirts the southwest edge of town. There is a parclo interchange with U.S. Route 70 and an interchange with Interstate 40. The business route meets AR 1 in north Forrest City, and AR 1 enters Caldwell and Colt before entering Cross County. South of Caldwell, AR 1 is near the historic Little Telico Creek Bridge, listed on the National Register of Historic Places.
The route now known as AR 1 first appears as a state highway in 1924, when the Arkansas General Assembly first created a state highway system. Arkansas State Road B-1 ran from the Louisiana state line near Wilmot north into Missouri, and was mostly unpaved. Upon creation of the U.S. Route system in 1925, the north and south portions of the highway were replaced by U.S. Route 67 and U.S. Route 165, respectively, shaping a more familiar AR 1 routing. Arkansas followed the trend to number in 1926, and B-1 became Arkansas Highway 1. The route remains very true to that original course today. The route was split apart in 1941 into AR 1 East and AR 1 West segments from Paragould north. AR 1 East continued north through Marmaduke and Rector. AR 1 West traveled into Corning. By 1955, AR 1W became Arkansas Highway 135, and AR 1E became AR 1. US 49 overlapped Highway 1 from Jonesboro to Piggott in 1978.
Major intersections
Mile markers reset at concurrencies.
Business routes
Arkansas Highway 1 has six business routes and one spur route. As cities have grown, bypasses have become necessary, and the former downtown alignments of AR 1 have become the business routes discussed here. The St. Charles spur route terminates at the site of the Civil War Battle of Saint Charles upon the White River. The Forrest City business route intersects major routes U.S. Route 70 and Interstate 40. De Witt, Marianna, Vanndale, and Cherry Valley all have business routes of less than. The Jonesboro business route is the longest, and intersects future Interstate 555.