SR 343 commences from a signalized intersection with US 68 in Yellow Springs.

SR 343 generally traverses a rural backdrop through Miami Township, Greene County with a mix of woods and open fields, and the occasional house along the way.

About one mile (1.6 km) east of US 68, SR 343 meets SR 370, the primary access route to John Bryan State Park, at its northern terminus.

SR 343 continues east, then starts to trend southeasterly, brushing the northeastern portion of John Bryan State Park just prior to entering Clifton.

Upon crossing into Clifton, SR 343 briefly ducks into Clark County, but re-enters Greene County, as it turns easterly, following North Street through the village prior to coming to an end at a T-intersection with SR 72.