When William Penn, and his surveyor Thomas Holme, laid out Philadelphia, he made one of the classic mistakes of inexperienced designers; he didn't visit the site first. At the new city's location, the Delaware and Schuylkill Rivers are about two miles apart and Penn laid out a city a mile wide, north to south and two miles long, east to west between the rivers. He then subdivided the city into four quadrants each having a square for open space at its center. It is a beautiful design, elegant in its simplicity and rationality - the design won an award from the American Society of Civil engineers in 1996.

Unfortunately the new settlers to Philadelphia all wanted to be located along the large river to the east, the Delaware, where the action was both socially and economically. Those who had bought parcels on the western edge of the city quickly traded for land closer to the Delaware. To get an idea of how Philadelphia's development really ended up happening , take a map of Philadelphia place the point of a compass at the Delaware River where Market Street intersects it. Draw arcs radiating out from this point and you have a diagram of how Philadelphia grew over time.

At the time of the American Revolution, development was mostly east of Eighth Street but stretched for several miles north and south along the Delaware River beyond the official city limits. Philadelphia, by some estimates, was the second largest English speaking town in the world with about 60,000 people living in the area. In spite of its success, it would look more like a small town to a visitor from the 21st century. Many blocks might only have a few houses facing the street with large yards separating each house. Modern zoning was unknown so that shops, taverns warehouses and churches would all be mixed with the houses. Fewer than 10% of the population owned their own house so many large homeowners would build smaller houses in the same property to rent out.
The Delaware Waterfront
Philadelphia in 1840