Upon crossing the marshy Oldmans Creek, CR 551 enters Woolwich Township in Gloucester County and becomes Auburn Road as it passes residential subdivisions before crossing CR 602 and heading into agricultural areas. The road enters areas of residential development again as it intersects CR 620 and CR 662. After crossing the Southern Railroad of New Jersey's Salem Branch line, the route continues into Swedesboro and becomes Auburn Avenue. The road is lined with homes as it meets CR 671 before coming to a junction with CR 605 and CR 694. At this intersection, CR 551 turns onto Kings Highway and passes through the residential and commercial downtown of Swedesboro, reaching the junction with the western terminus of CR 538. The route crosses the Racoon Creek back into Woolwich Township and intersects CR 653 before passing a mix of farms and development as it comes to US 322/CR 536. CR 551 continues through more agricultural areas as it has junctions with CR 672 and CR 684. Continuing into East Greenwich Township, the route heads into areas of residential subdivisions as it crosses CR 607 and CR 664. After passing through some woods, the road heads into the residential community of Mickleton and intersects CR 673. In the community of Clarksboro, CR 551 reaches junctions with CR 667 and CR 707. The route crosses the Southern Railroad of New Jersey's Salem Branch before passing more homes in the community of Mount Royal, where there is an intersection with CR 678. CR 551 crosses the Mantua Creek into West Deptford Township and heads east between oil tanks to the north and residential areas to the south as it intersects CR 648, CR 643, and CR 656. The road continues near more homes and tank farms before crossing CR 660, where the setting becomes mainly residential. CR 551 enters Woodbury and becomes Salem Avenue as it enters commercial areas, crossing Conrail Shared Assets Operations' Penns Grove Secondary before reaching an intersection with Route 45.