How Philly Got Its Shape

September 26, 2013 | by Steve Currall


Later printing of Thomas Holme's 1687 Map of "The Improved Parts of Pennsilvania," John Harris printing, London, 1697

Later printing of Thomas Holme’s 1687 Map of “The Improved Parts of Pennsilvania,” John Harris printing, London, 1697

In 2008, playwright and screenwriter Mark Stein dabbled in popular history, with the release of How the States Got Their Shapes. The book, the result of a fair amount of research in the stacks of the Library of Congress, offered a border-by-border explanation of the often curious contours of each of the fifty American states. By virtue of its framing, Stein’s exegesis is forced to touch upon a wide array of geographic, political, and economic issues for each state, at times conflating traditional historical narratives; any thorough understanding of the silhouette of Virginia for example, demands forays into the seventeenth century European mercantile system, the beginnings of American notions of federalism, as well as the geography and culture of antebellum slaveholding. Such a refreshing approach proved wildly popular, encouraging the History Channel in 2010 to once again live up to its name, airing a series exploring the topic further.

Barraged as I am with images of the shape of Philly by everything from carefully prepared annual community development corporation reports to mass produced typography prints hanging in certain Center City storefronts, it wasn’t long until I began to ponder what insights Philadelphia’s shape had to offer.

Starting with an informal poll, I discovered that a municipality’s shape is not as well known as I first suspected. Some lifelong Philadelphians, suspecting that I was attempting to psychoanalyze them, confused the unmarked shape that I presented with a Rorschach ink blotch. To another, it was the Canadian province of Manitoba.

Philadelphia: now available in brown plaid | T-shirt © 2004 by Edit Apparel

Philadelphia: now available in brown plaid | T-shirt © 2004 by Edit Apparel

Yet I also came across those who shared an appreciation for the shape’s role as suitable shorthand iconography for Philly not unlike a stylized Liberty Bell. (If only our Swedish-inspired flag could elicit the same response.) In the course of my research, I have found, much like Mark Stein, that rather than some arbitrary collection of lines on a map, the shape explains a quarter-millennium of Philadelphia’s story: from its genesis as an sylvan abstraction of Restoration Britain, to its halcyon days as the intellectual and political nexus of an emerging nation, to its dominance of American manufacturing. Indeed, Philadelphia’s is a shape reflecting the clash of empires, and the revolutionary zeal of a bygone age of reason. One just might say that Philadelphians don’t grant their city enough credit.

(Unlike many other American cities, where the municipality is split among numerous counties [NYC being comprised of five: Bronx, Kings, New York, Queens, and Richmond], Philadelphia’s boundaries are “coterminous” with those of its county. This has been the case since 1854, when the Act of Consolidation dissolved the county government and replaced it with a sturdier, more inclusive city government.)

As Always, It Starts With Penn…

Since the destruction of colonial Dutch America by the English fleet in 1664, the woodlands west of the Delaware River—being sparsely inhabited by several hundred aging Swedish settlers and their children—were by necessity the mere extended administrative responsibilities of the Province of New York. The Duke of York (eventually King James II), now lord of English America from Long Island down to the Delaware Bay, quickly settled old debts with George Carteret with the gift of New Jersey, and extorted the established landowners of the Delaware Valley for every last schilling. (Snatching back their lost kingdom had proved an expensive undertaking for the Stuart brothers after all.) By the early 1680s, it was Charles’ turn to make good. Granting a proprietorship over some 45,000 square miles of American real-estate with only an inland port seemed an acceptable tradeoff with William Penn, an obnoxious Quaker who held right to £16,000 from the royal coffers.

Under the old King's Highway: Frankford Avenue bridge over Poquessing Creek, looking from Philadelphia toward Bucks County | Photo: Bradley Maule

Under the old King’s Highway: Frankford Avenue bridge over Poquessing Creek, looking from Philadelphia toward Bucks County | Photo: Bradley Maule

Penn already owned shares in a precursor to his Quaker utopia across the river in West Jersey, but Pennsylvania would be his alone. Avoiding much of the ad hoc planning characteristic of so many other colonial start-ups, Penn dictated the administrative infrastructure of Pennsylvania soon after landing at Upland (now Chester, Delaware County) in August, 1682. Three counties would be created: Chester, named after the English hamlet of the same name; Bucks, after County Buckinghamshire; and Philadelphia County, to be anchored by Philadelphia City.

Logically enough, these counties were to run diagonally from their source at the Delaware River northwestward to as far as treaties with the Lenape and Susquehannocks would allow, remaining parallel with the bend of the Delaware beginning at Penn’s country estate at Pennsbury, Bucks County. Two waterways were selected by which to form the boundaries of Philadelphia County: Potquessin (Poquessing) Creek (aided by a straight line starting in today’s Somerton) and the mighty Schuylkill.

City Line Avenue's bridge over the Schuylkill River, where Philadelphia's boundary turns 90º | Photo: Bradley Maule

City Line Avenue’s bridge over the Schuylkill River, where Philadelphia’s boundary turns 90º | Photo: Bradley Maule

But this latter line only explains the city’s shape down to City Line Avenue, at which point it runs southwest along that telecommunications thoroughfare to Cobbs Creek, finally meandering down Darby and Bow Creeks until returning to the Delaware.

So why does West Philadelphia jut toward Upper Darby and Haverford Township? In short, William Penn forgot to do some math.

In order to initially attract serious investors to the project soon after securing his royal charter in early 1681, Penn agreed to “Certaine Conditions or Concessions” with the First Purchasers of land in Pennsylvania: for every 100 acres they bought in the countryside, they would be entitled to two acres of Philadelphia “city lots.” Yet Penn, always more the visionary than the judicious administrator, failed to calculate the acreage necessary for such a scheme prior to settling on a location for his capital city. The unassuming Lenape village of Coaquanock at the narrowest breadth between the Delaware and Schuylkill rivers proved too small a locale to meet these contractual obligations, so Penn stretched the definition of a “city lot” to include an altogether novel category of land: the liberty lands. Penn had John Noble survey 16,000 acres adjacent to the city in February 1683 to mark these “liberties,” to be reserved for the “good and benefit” of the First Purchasers. In order to ensure their concentration around the city, these liberties—and by extension, Philadelphia County—would need to spill over to the woods on the opposite side of the Schuylkill. Because the liberties on the west bank of the river were regarded as being inferior to those immediately north of the city, (Extending the grid through West Philadelphia in the late 19th century would indeed prove something of a chore.) Penn marked the two at different ratios; an acre of the western liberties was equivalent to 4/5 of one east of the river.

The Holme Map: For God & Profit

Screen shot 2013-09-26 at 1.33.22 PM

In a way, the modern shape of Philadelphia may be found in the earliest map of southeastern Pennsylvania, that of Surveyor General Thomas Holme and his deputy Robert Longshore. Personally commissioned by William Penn just before he left his nascent colony in 1684, the map stands as a truly remarkable achievement. Holme’s biographer, Irma Corcoran, has rightly called it the “greatest of early American maps,” and a “masterpiece.” Lacking the benefit of modern technology, and forced to deal with the intransigence and fraudulence of his deputy surveyors, Holme was able to depict, with relative accuracy, some 1,800 square miles of Penn’s wilderness. Finishing his draft in 1687, he sent his work to England, for printing and distribution later that year. Those Londoners who first gazed upon the large map (seven sheets of paper, 33.5” by 55.5”) could trace the delineations of most large-to-medium sized tracts then settled within what historian Walter Klinefelter has deemed the most ambitious “disposal of real estate on a scale never before undertaken…the most enterprising ever put into operation for peopling a wilderness.”

During one book discussion, Mark Stein explained the derivation of the semicircular border between New Castle and Chester counties, musing that the “arc inscribes in the shape of Pennsylvania its Quaker past.” Designed to provide a buffer between older Swedish and Dutch colonists and the idealistic Quakers then arriving from across the sea, the 12-mile radius from New Castle Towne, tells of the Society of Friends’ steadfast faith in the geometric order of the universe. Philadelphia’s shape likewise displays this perpetual stamp of Quakerism, as Penn stressed to Holme that his province should be settled in an logical, contiguous fashion “to the end that the Province might not lie like a Wilderness as some others yet do by vast vacant tracts of Land, but be regularly improved for the benefit of Society.”

The serrated nature of much of Philadelphia’s boundaries, arduously traced by late seventeenth century surveyor wheels, then symbolizes the dualistic legacy of Penn’s “Holy Experiment:” a place for both divine order and profitable land speculation.

Philadelphia Split In Half

For its first century, Philadelphia County included all of Montgomery County. The story of the creation of the latter best explains the specifics of the shape of Philly as we know it today.

By the early 1780s, with American independence all but ensured after the Siege of Yorktown, an increasing choir of farmers from the northern environs of the county began to petition the Commonwealth of Pennsylvania for the creation of a new county. We are told by the lawmakers of the time that the rationale lay in the often burdensome journeys that were required of such residents if and when they needed to travel to the city for official business. While this was surely a contributing factor in expediting the legislation, it was likely little more than tactful language.

If the roads leading to and from Philadelphia City were insufficient, the internal road system of the northern county was practically non-existent. Rather it was the “feeling that the city and parts adjacent enjoyed more benefits from the public funds than did the rest of the county,” judge Irving P. Wanger would conclude, upon his county’s centennial celebrations in 1884. Some of the petitions sent to the government even asked that the separation be limited to taxation itself.

City Line Avenue (foreground, left side) and the Schuylkill River separate Philadelphia and Montgomery Counties | Photo: Bradley Maule, 2003

City Line Avenue (foreground, left side) and the Schuylkill River separate Philadelphia and Montgomery Counties | Photo: Bradley Maule, 2003

By February of 1784, the General Assembly conceded as to the separation’s necessity and the matter was referred to a committee for further consideration. For most of that summer’s planning stages, the committeemen assumed that the seceding county would take more of Philadelphia with it than it eventually did—everything down to the limits of Northern Liberties. In fact, while reporting on the arrangements underway to decide upon the location of the new county court house, the Pennsylvania Gazette referred to the projected municipality in no-less inclusive terms than “the county of Philadelphia, when divided from the city.”

Yet when it came time for the bill to leave committee and be considered by the legislature as a whole, Philadelphia City’s representatives were able to counter what they saw as an overly generous allocation for the planned county, at the expense of the domination of the City. They called for the line of separation to lay as far north as Conshohocken, yet this amendment was also defeated.

The next proposed line would prove to be the last. Several townships, stricken out of the prior amendment, were retained by Montgomery County: Horsham, Abington, Cheltenham, Whitemarsh, Springfield, and even Lower Merion on the opposite bank of the Schuylkill. The elongated township of Moreland was to be split in two. On September 10, 1784, “an Act for erecting part of the County of Philadelphia into a separate County” was formally approved with a vote of 36-16.


The final alteration to Philadelphia’s shape was a relatively minor one.

Since 1878, when the Pennsylvania Railroad first laid the Philadelphia, Newtown and New York line (today’s Fox Chase Regional Rail line), an 84-acre triangular wedge of land had in effect been excluded from the rest of Cheltenham township.

Details of 1910 Smith Map & 1921 Bromley Map

Details of 1910 Smith Map & 1921 Bromley Map | Details prepared by Alan Trachtenberg

In May of 1915, the state legislature approved a measure permitting any county to petition a neighboring county to accept territory that was inaccessible by public highway from the greater portion of that county.

This then allowed the Court of Quarter Sessions of Montgomery County on November 19, 1915 to return to Philadelphia that segment (between Cheltenham & Hasbrook Avenues and the rail line) after 131-years of having been in Montgomery County.

This evidently encouraged City officials for further aggrandizement, with Mayor Thomas B. Smith (R, 1916-1920) promoting a scheme to annex the riverfront portion of Delaware County as far as Chester. But of course, this did not happen, and in spite of a lot of paved over gray area on Philadelphia International Airport’s runways, Philadelphia’s 135 square miles have retained their shape ever since.


About the Author

Steve Currall Stephen Currall recently received his BA in history from Arcadia University. Before beginning doctoral studies, he is pursuing his interest in local history, specifically just how Philadelphians engage their vibrant past. Besides skimming through 18th century letters, Steve is also interested in music and travel.


  1. John G. Livewell says:

    GREAT ARTICLE!!!! Steve, you always hit a home run.

  2. Seth Itzkowitz says:

    Good article — I was aware of the Montco giveback (although I thought it was 88 acres and that the city was 129 sq. miles.

    You may wish to look into how in the 1930s, Rockledge wanted to merge iwth Philadelphia and the city turned the borough down.

  3. Alexander Fidrych says:

    What’s the story behind the course of the city border through that “lot of paved over gray area” at PHL anyway? The best guess I’ve been able to come up with results from comparing maps drawn by the British of the Siege of Mud Island Fort (Fort Mifflin) to current aerial photography. To my eye, the current border vaguely corresponds to the former courses of Bow, Kingsess and Mingo Creeks, with former Boon’s and Carpenter’s Island given to Chester (now Delaware) County and former Province Island to Philadelphia. Bow Creek once connected Darby Creek to the Delaware almost directly opposite the mouth of Mantua Creek and the Holme map indicates that it originally formed this part of the border between Chester and Philadelphia counties, but for whatever reason Boon’s and Carpenter’s Islands appear to have been carved out at some point and given to Chester (now Delaware) County.

  4. Harry Kyriakodis says:

    Great article! I always wanted to learn about that last bit that was added… And consider this: Philadelphia occupies a bit more ground-space than the cities of Boston (about 48 square miles) and Baltimore (about 81) combined. (Interestingly, the geographic center of Philadelphia is approximately at 6th and Erie Streets in North Philadelphia.)

  5. Ryan says:

    Thomas Holme was my 10th great-grandfather .

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