It winds its way northeast through the hilly terrain of the Highland Rim for several miles to cross into Marshall County at an interchange with I-65 (Exit 22).

[2] The highway then passes through the town of Cornersville, where it has a long concurrency with SR 129, before continuing northeast to enter Nashville Basin and the city of Lewisburg at an intersection with US 31A Business.

SR 99 splits off and goes east shortly thereafter and US 31A then leaves Chapel Hill and passes through rural farmland for several miles to cross into Williamson County.

They pass by some more businesses before SR 50 splits off and heads northwest along College Street and Franklin Avenue.

US 31A Bus/US 41A Bus turn northeast along Verona Avenue and pass through some neighborhoods before they come to an end at an intersection with US 31A/US 431/SR 106/SR 272 (N Ellington Parkway/Nashville Highway).