The High Street was the familiar name of the principal street in nearly every English town at the time Philadelphia was founded. But if Philadelphia was indebted to England for the name of High Street, nearly every American town is, in turn, indebted to Philadelphia for its Market Street. Long before the city was laid out or settled, Philadelphia's founder, William Penn, had planned that markets would be held regularly on the wide High Street. The city's first market stalls were situated in the center of the thoroughfare starting at Front Street and proceeding west eventually to 8th Street. The stalls soon became covered and were not taken down as planned. Later, additional covered sheds appeared west of Center Square as the city expanded westward. The street began to be called Market Street around 1800. The road's new name was made official by an ordinance of 1858, ironically, just a year before the market sheds were ordered removed.
Market Street has been called the most historic highway in America because of the various historic sites along its eastern section. Many of Benjamin Franklin's activities were centered along Market Street. His house was located near the intersection of Fourth Street, and it is said that he may have performed his famous kite-flying experiment near Tenth and Market Streets. Thomas Jefferson wrote the Declaration of Independence in a boarding house (the Graff or Declaration House) once located at the Seventh Street intersection. The mansion of Robert Morris, financier of the American Revolution, was located near Sixth and Market Streets. This house was used by George Washington and John Adams as their residences during their time as President in Philadelphia. (The house was more or less on the site of the northern part of the modernday Liberty Bell Center.) Several important finance and publishing firsts also occurred along Market Street between Second and Fourth Streets during the 1700s. Market Street is still one of the principal locations of business and commerce in Philadelphia.
Market Street runs from Upper Darby Township, Pennsylvania to Front Street in Center City, Philadelphia. At Front Street, a bridge over Interstate 95 brings traffic from Penn's Landing, on the western bank of the Delaware River, onto westbound Market Street. Market Street runs one way, eastbound, between 20th Street and 15th Street, with westbound traffic diverted onto JFK Boulevard.
Market Street is interrupted between 15th Street and Juniper Street, with Philadelphia City Hall sitting on the block where Market Street's intersection with Broad Street would be. A pedestrian-only path continues Market Street across the City Hall block. Between 12th Street and roughly 20th Street, Market Street is heavily commercial, with office skyscrapers rising on both sides.
The street continues westward, crossing over the Schuylkill River via the Market Street Bridge, into and through University City and West Philadelphia. Market Street terminates at 69th Street in Upper Darby, Pennsylvania, where PA Route 3 continues onto West Chester Pike throughout the Delaware County and Chester County suburban areas. It is interesting to note that Eastbound PA Route 3 is also known as Market Street in downtown West Chester.
Perhaps the most famous landmark is Independence National Historical Park, located at Fifth and Market Streets. Home to the Liberty Bell, Independence Hall, and National Constitution Center, the complex is the heart of Philadelphia's Old City neighborhood.
Reading Terminal, the former grand railroad station for the Reading Railroad is located on the northeastern corner of 12th and Market Streets. It is now used as the grand entrance to the Pennsylvania Convention Center.
Philadelphia City Hall sits atop Market Street's intersection with Broad Street. Commuters can access the Market-Frankford Line, Broad Street Line, Subway Surface Lines, and Suburban Station through the 15th Street Headhouse (among other access points) across from City Hall.
One Liberty Place, formerly Philadelphia's tallest building, is located at the southeast corner of 17th and Market Streets. (It was surpassed in height by the Comcast Center, located a block to the north, in June 2007).
30th Street Station, a major commuter rail line terminal, is located at the intersection of 30th and Market Streets.