State Route 172 (SR 172) is a 24.420-mile (39.300 km) state highway that serves as an east-west connection between Vina and Bear Creek through Franklin and Marion Counties.

SR 172 intersects SR 19 at its western terminus and SR 13 at its eastern terminus.

[2] From this point, SR 172 travels in a southeasterly direction where it meets SR 187 in Hodges.

[3] From Hodges, the route continues generally in its eastern direction and intersects US 43/SR 17 in Hackleburg.

[4] From this point, SR 172 again continues generally in an easterly direction and intersects SR 237, in addition to sharing a .435-mile (0.700 km) concurrency with SR 241, prior to reaching its eastern terminus at SR 13 in Bear Creek.