Chester and Delaware counties PA 3 begins at an intersection with
US 322 Bus. (High Street) in the downtown area of the borough of
West Chester in
Chester County near the historic
Chester County Courthouse. From here, the route heads northeast on the
one-way pair of East Market Street eastbound and East Chestnut Street westbound. The one-way streets carry two lanes in each direction as they pass downtown businesses. At the intersection with Matlack Street, the westbound direction of PA 3 shifts from East Chestnut Street one block south to East Gay Street. The route continues to follow East Market Street eastbound and East Gay Street westbound through commercial areas, passing north of the terminus of the
West Chester Railroad at the
West Chester station along East Market Street. PA 3 leaves West Chester for
West Goshen Township and intersects Montgomery Avenue (westbound only) and Garfield Avenue/Westtown Road before it comes to an eastbound exit and westbound entrance with Paoli Pike. At this point, both directions of the route join and head east along four-lane
divided West Chester Pike, passing through residential areas in the community of
Chatwood. PA 3 comes to a
partial cloverleaf interchange with the
US 202/
US 322 freeway and runs past businesses and some homes. The road curves east-southeast at the
Strasburg Road intersection and crosses into
East Goshen Township, where it continues past suburban neighborhoods and commercial establishments, crossing the
East Branch Chester Creek and passing through the community of
Goshen. PA 3 enters
Westtown Township and reaches an intersection with
PA 352, forming a short
concurrency with that route before PA 352 splits to the southeast. The road heads east through wooded areas with residential subdivisions as it continues into
Willistown Township. The route intersects the eastern terminus of
PA 926 and curves east-northeast through a mix of fields and woodland with some homes, crossing the
Ridley Creek before coming to a junction with Delchester Road. PA 3 enters
Edgmont Township in
Delaware County as it passes to the north of
Ridley Creek State Park. The road continues east with some homes and businesses, intersecting Providence Road. After passing to the south of a shopping center, the route crosses
Crum Creek into
Newtown Township and heads south of the Delaware County Veterans Memorial, running past a mix of fields and development. PA 3 curves east at the Boot Road intersection and passes between a business campus that includes
SAP's North America headquarters to the north and a residential neighborhood to the south. The road heads into business areas and reaches intersections with Bishop Hollow Road and
PA 252 in the community of
Newtown Square. Following the PA 252 intersection, the route continues east through a mix of suburban residential and commercial areas. At the Media Line Road junction, PA 3 crosses into
Marple Township and soon intersects Springfield Road. The road passes more homes and businesses and comes to a junction with
PA 320 in the community of
Broomall. The route continues near suburban neighborhoods with some businesses before it reaches a partial cloverleaf interchange with
I-476. Past the I-476 interchange, PA 3 intersects Lawrence Road and crosses the
Darby Creek into
Haverford Township, where another section of Lawrence Road splits to the north. The road continues east past homes and businesses as it passes through the community of
Havertown, reaching a junction with
Eagle Road. PA 3 has an intersection with Manoa Road as it passes to the north of the
Llanerch Country Club, continuing through suburban development. Farther east, the route crosses
Naylors Run and heads into the community of
Llanerch, where it intersects
Darby Road a short distance before coming to a junction with
US 1. After crossing US 1, PA 3 enters
Upper Darby Township and continues past suburban businesses and homes. The road crosses State Road and heads into more urban areas of residential and commercial development. A set of
SEPTA trolley tracks begins running in the median before the route comes to Terminal Square, where it crosses SEPTA's
Media–Sharon Hill Line at-grade and intersects Victory Avenue/Garrett Road. Past this, PA 3 heads east on four-lane undivided
Market Street as it passes between SEPTA's
69th Street Transportation Center to the north and urban businesses to the south, gaining a median before the 69th Street intersection. The route becomes undivided again and runs past more commercial development, forming the border between the borough of
Millbourne to the north and Upper Darby Township to the south. PA 3 heads past some homes before turning into a divided highway at the eastern edge of Millbourne as SEPTA's
Market–Frankford Line rises to pass over the road.
West Philadelphia PA 3 crosses the
Cobbs Creek into the city of
Philadelphia in
Philadelphia County, where it immediately splits from Market Street by turning south onto Cobbs Creek Parkway at the
63rd Street station on the Market–Frankford Line. The route follows four-lane undivided Cobbs Creek Parkway between woods along the creek to the west and urban development to the east before it splits east onto a one-way pair. The eastbound direction of PA 3 follows
Chestnut Street while the westbound direction of PA 3 follows
Walnut Street a block to the south. Chestnut Street carries three lanes of one-way eastbound traffic while Walnut Street carries two lanes of one-way westbound traffic. PA 3 follows Chestnut and Walnut street east through residential areas of
West Philadelphia, passing several blocks of
rowhouses with some businesses. Walnut Street passes to the north of
William L. Sayre High School between 59th and 58th streets while Chestnut Street passes south of
West Philadelphia High School before crossing 49th Street, south of the
Community College of Philadelphia's West Regional Center past 48th Street, and south of
West Catholic Preparatory High School prior to crossing 45th Street. Farther east, the route reaches the
University City neighborhood of Philadelphia, where Walnut Street runs along the edge of the
University of Pennsylvania campus. The streets cross a SEPTA trolley track at 40th Street. Upon reaching
US 13, westbound PA 3 shifts from Walnut Street to Market Street, running concurrent with US 13 southbound on four-lane divided 38th Street between Market and Walnut streets; 38th Street carries a SEPTA trolley track in the northbound direction. East of US 13, westbound PA 3 follows on Market Street, a three-lane road with a
center left-turn lane. At this point, SEPTA's Market–Frankford Line runs underneath Market Street, with SEPTA's
Subway–Surface Trolley Lines joining at 36th Street. Eastbound PA 3 continues east on one-way Chestnut Street. The route passes several multistory commercial buildings as it runs through the northern part of the
Drexel University campus. At 33rd Street, eastbound PA 3 turns north and joins the westbound direction on Market Street, continuing east. Upon reaching 32nd Street, PA 3 splits into another one-way pair, with eastbound PA 3 continuing east along Market Street and westbound PA 3 following four-lane John F. Kennedy Boulevard, both being two-way streets. The route passes under
CSX's
Harrisburg Subdivision railroad line before coming to the 30th Street intersection at
30th Street Station, which serves
Amtrak's
Northeast Corridor railroad line, the
SEPTA Regional Rail system, and
NJ Transit's
Atlantic City Line. The eastbound direction passes to the south of the train station and north of the city's
former main Post Office facility as a four-lane undivided street. The westbound direction bends north around the train station, running along a one-way street with two lanes of traffic that heads north on Schuykill Avenue and crosses under the SEPTA tracks before turning west on Arch Street. It then passes to the south of the
Cira Centre and curves south as 30th Street under the SEPTA tracks again before turning west on John F. Kennedy Boulevard. Immediately east of 30th Street Station, PA 3 has an interchange with
I-76 (Schuylkill Expressway) before it crosses over the
Schuylkill River and then the
Schuylkill River Trail and CSX's
Philadelphia Subdivision railroad line on the river's east bank on the
Market Street Bridge eastbound and the
John F. Kennedy Boulevard Bridge westbound.
Center City Philadelphia At this point, PA 3 heads into
Center City Philadelphia on four-lane undivided Market Street eastbound and four-lane divided John F. Kennedy Boulevard westbound. The streets pass several downtown skyscrapers, with the westbound direction running south of SEPTA's
Main Line tracks, which head into the
Center City Commuter Connection tunnel at 20th Street. At the 20th Street intersection, both directions of PA 3 become one-way streets, with Market Street carrying three lanes of eastbound traffic, with the fourth right-most lane serving as a
bus lane, and John F. Kennedy Boulevard carrying four lanes of westbound traffic as it heads into the
Penn Center business district. At the 19th Street intersection, the right-most lane on John F. Kennedy Boulevard becomes a bus lane. Eastbound PA 3 passes to the north of
Liberty Place between 17th and 16th streets while westbound PA 3 passes to the south of the
Comcast Center between 18th and 17th streets,
Suburban Station of SEPTA Regional Rail between 17th and 16th streets, and
LOVE Park between 16th and 15th streets. PA 3 reaches its eastern terminus at
PA 611 (which runs north-south along
Broad Street through Philadelphia) at 15th Street, which forms the western part of Penn Square around
Philadelphia City Hall. ==History==