Highway 123 begins in the Arkansas River Valley in Clarksville, but quickly becomes a winding mountain highway, spending most of its length in the Ozark Mountains. The route is one of the few north–south corridors in the dense and sparsely populated forest, and passes many campsites, rivers, and hiking trails for recreational use. The route is a rural, two-lane road its entire length. Highway 123 begins in Clarksville at Highway 103 in a residential subdivision. It runs east past Johnson Regional Medical Center and the historic Pioneer House before entering Lamar, where it overlaps US 64. Near downtown Lamar, Highway 123 turns north from US 64, forming an overlap with Highway 164 to Hagarville. North of Hagarville, the route enters the Ozark National Forest, becoming a winding rural road. It enters the Piney Creeks Wildlife Management Area, where it passes the Haw Creek Falls Recreation Area, bridges Big Piney Creekon a historic structure, crosses the Ozark Highlands Trail near Big Piney Creek, and forms the southern border of the Hurricane Creek Wilderness Area in the northeast corner of Johnson County. The highway enters the northwest corner of Pope County, intersecting Highway 7 and Highway 16 at Sand Gap. The routes begin an overlap northbound, passing the Thomas J. Hankins House, listed on the National Register of Historic Places. In Newton County, the concurrency ends at Lurton, with Highway 7 and Highway 16 turning northwest toward Jasper and St. Paul. A wye connection provides non-truck travelers access to Highway 7 and Highway 16 at Lurton. Highway 123 winds north to Mount Judea, where an officially designated exception with Highway 74 forms. Highway 123/Highway 74 serve as the eastern terminus of Highway 374 south of Piercetown, when Highway 74 turns west toward Jasper. Highway 123 continues north, passing through the western side of the Gene Rush WMA and crossing the Buffalo National River near Carver Day Use Area, a river landing and campsite maintained by the National Park Service. Highway 123 runs north to Western Grove, where it terminates at US 65 and US 65B.
History
Highway 123 was created by the Arkansas State Highway Commission after the 1926 Arkansas state highway numbering, appearing on the 1927 state highway map. The highway started at Highway 23 in St. Paul and ran north to Highway 7 near Freeman Springs. By the 1929 map, the route had been deleted from Highway 23 in St. Paul to a hanging end south of Oark, with the west end being moved from Clarksville to US 64 in Lamar, and the east end moving to Highway 7 and Highway 16 at Pelsor. The highway's routing remained unchanged until 1936 or the first half of 1937, when the section between Oark and Clarksville became Highway 103, with the former alignment of Highway 103 to Western Grove becoming Highway 123. This alignment change resulted in a Highway 123 alignment between Lamar and Western Grove very similar to the highway's present-day routing. It was extended to Clarksville in 1963. The Harrison route was created on March 26, 1975 from US 65B to North Arkansas Community College. It was extended south to Salmon Lane on January 30, 1980. The extension was made at the request of the County Judge of Boone County, in exchange for decommissioning Highway 397 near Omaha.
Major intersections
Mile markers reset at some concurrencies.
Lurton loop
Highway 123Y Spur is a spur route at Lurton. It is an unsigned state highway. ;Route description The route provides more direct access for northbound traffic to Highway 7. Due to its steep grades and curves, trucks are not allowed on the route. ;History Highway 123Y is a former alignment of Highway 7. It was removed from the state highway system on October 31, 1956 following realignment of Highway 7, but was restored November 9, 1960. ;Major intersections
