Highway 108 western terminus at US 59/US 71. This junction is entirely in Texas.
The northern segment of Highway 108 begins at the Oklahoma state line as a continuation of State Highway 87. It heads to the northeast through Little River County towards Foreman. On the southern edge of Foreman, a spur route, Highway 108S, splits off to the south to intersect Highway 32 / Highway 41 and Highway 108 turns to the north. At Highway 32, which is Tracy Lawrence Avenue at this location, Highway 108 turns to the east and follows Highway 32. At Highway 41, known as Madden Street in Foreman, Highway 32 turns to the south and Highway 108 continues east.
East of Foreman, Highway 108 continues to the northeast towards Alleene. South of Alleene, the route intersects Highway 234 at a four-way stop. All traffic at this intersection must turn to stay on the same numbered route; Highway 108 represents the western and southern branches and Highway 234 represents the northern and eastern branches. Now heading south and east, Highway 108 travels 10 miles (16 km) to U.S. Highway 59 / U.S. Highway 71 north of Ashdown.
Highway 108 Spur (AR 108S, Ark. 108S, and Hwy. 108S) is a short, east–west highway in Little River County in southwest Arkansas. Running only 0.77 miles (1.24 km) in length, its western terminus is at an intersection with Highway 108 6 miles (9.7 km) west of the Oklahoma state line. Its eastern terminus is at an intersection with Highway 41 1 mile (1.6 km) south of Foreman.
^ abcPlanning and Research Division (2010). "Arkansas Road Log Database" (Database). Arkansas State Highway and Transportation Department. Archived from the original on 23 June 2011. Retrieved June 9, 2011.