PA 183 begins at US 422 Bus. in the downtown area of the city of Reading in Berks County. The northbound direction begins at the intersection of North 3rd Street and Franklin Street and heads west concurrent with westbound US 422 Bus. on one-way Washington Street, carrying three lanes of traffic. Southbound PA 183 ends at the intersection of 2nd Street and Penn Street, following US 422 Bus. westbound south on North 2nd Street, a one-way street with four lanes of traffic. Past the concurrency with US 422 Bus., PA 183 heads west on the two-lane undivided Washington Street, passing to the north of Reading Area Community College. The route passes through commercial areas before turning north onto Front Street and entering residential areas. At the intersection with Walnut Street, PA 183 splits into a one-way pair that carries two lanes in each direction, with the northbound direction remaining along Front Street and the southbound direction following Schuylkill Avenue. Front Street heads north while Schuylkill Avenue angles northwest, with the one-way pair continuing through areas of homes and passing over Norfolk Southern's Harrisburg Line #2. Schuylkill Avenue becomes a two-way, two-lane road at the Green Street intersection. Northbound PA 183 turns west on two-way, two-lane Windsor Street to rejoin southbound PA 183 on four-lane undivided Schuylkill Avenue. Along this one-way pair, northbound PA 183 is city-maintained. The highway heads northwest, passing over Norfolk Southern's Spruce Street Industrial Track and the Schuylkill River on a bridge that also carries the Schuylkill River Trail.