One segment runs from Highway 264 in Siloam Springs north to the Missouri state line.

For the northernmost few miles of the overlapping stretch of road, AR 43/SH-20 turns toward the west, no longer straddling the state line.

[3] The northernmost few feet of AR 43/SH-20 are completely in Arkansas, as the Arkansas/Missouri/Oklahoma tripoint is on the west side of the highway.

[7] Minor relocations also took place around Lead Hill following construction of Bull Shoals Lake in 1954.

[10] The new segment was rerouted within Siloam Springs as part of a reorganization of the city's highways on July 17, 1996.