Hwy. 345 begins at the intersection of US 62 BUS, Combs Avenue, and Cotter Road in Cotter. It first heads south on Cotter Road crossing a railroad at-grade. It runs northeast through the southern part of Cotter paralleling the White River before zig-zaging its way north when it enters Gassville and terminates at US 62/US 412.
The other segment of Hwy. 345 begins at the intersection of Lakeview Drive and US 62/US 412. It heads north for about 0.33 miles (0.53 km) on Lakeview Drive before turning east onto Vine Street and terminating at Hwy. 126.