Here, PA 147 becomes Market Street and runs past homes before coming to a square in the center of town, where it becomes a divided highway and intersects the southern terminus of US 209, which is split into a one-way pair.

The road leaves Millersburg for Upper Paxton Township again and becomes unnamed, heading through a mix of fields and woods with some development a short distance to the east of the Buffalo Line.

The road curves north away from Mahantango Mountain and passes through the community of Paxton, continuing through a mix of farmland and woodland immediately to the east of the Norfolk Southern tracks, with the Susquehanna River further to the west.

[3][4] PA 147 crosses the Mahantango Creek into Lower Mahanoy Township in Northumberland County and continues through a mix of farm fields and woods with some residences, curving northeast and running further from the Susquehanna River and the Buffalo Line.

The road curves to the northeast, with the Susquehanna River and Buffalo Line a short distance to the west, and enters the borough of Herndon, where it becomes South Main Street and passes residences.

PA 147 continues through more wooded areas of the borough before heading past more homes with a few businesses, passing through the center of Herndon and becoming North Main Street.

The route heads north through rural areas further east from the river and railroad tracks before coming to the community of Selinsgrove Junction and closely following them again.

The road enters Upper Augusta Township and curves northeast further from the Susquehanna River and the Norfolk Southern line, heading through farmland with some residences.

[3][5] The route curves north and comes to a bridge over the Buffalo Line and Shamokin Creek, at which point it enters the city of Sunbury and becomes South Front Street.

US 15/PA 147 head northwest along the border between Shamokin Dam to the west and Monroe Township to the east, becoming undivided and running through wooded areas with some development.

The road fully enters Monroe Township and turns west, becoming unnamed and transitioning into a divided highway with a wide median as it runs through woodland with some fields and development.

The route curves north-northeast into farmland and comes to the northern terminus of the Central Susquehanna Valley Thruway as it continues along a freeway, reaching a diamond interchange with PA 45 to the east of the community of Montandon.

The freeway runs north-northeast through a mix of fields and woods to the east of the borough of Milton and comes to a diamond interchange serving PA 642, at which point it crosses into Turbot Township.