The southern terminus is at State Route 3038 (SR 3038, Bridge Valley Road) in the community of Pequea along the east bank of the Susquehanna River in Martic Township.

The route runs north through farmland before it curves northeast into wooded areas and crosses the Conestoga River into Lancaster Township.

The road continues north between a mix of farmland and residential development to the west and wooded areas along the Conestoga River to the east.

PA 324 passes to the east of a sewage treatment plant before it continues into commercial areas and intersects the southbound direction of US 222/PA 272 in the community of Engleside.

Past this, the route becomes one-way northbound with one lane of traffic and enters the city of Lancaster, heading northeast through urban residential and commercial areas on South Queen Street.

PA 324 reaches its northern terminus upon merging with northbound US 222/PA 272, with those two routes continuing north along South Queen Street.

Meanwhile, the remainder of the road between Pequea and Lancaster was designated as the eastern portion of PA 124, which continued west across the river to York.