Maps of Philadelphia Churches, Part 1

U.S. Census data shows overall trends across the U.S., in the service of providing a broad view of national trends, from populations shifts to immigration. However, it is done every ten years, and can’t track everything. I thought it’d be interesting to make maps based on the locations of religious institutions – each these accounts for a small group of people (10-1,000), and many groups track some basic statistics on their members (number of attenders, race, etc), on a yearly basis, more frequent than the census. I believe that visualizations that show the way people move and are distributed will help people better understand the changes they face- when churches and schools close, many are faced with the difficult experience of losing childhood memories, without an understanding of macro trends.

It’s become very easy to acquire map-making software (I’m using¬†TillMill) and data to populate maps.¬†The following map shows gray points for every church in Philadelphia, as reported by Google Maps. The overlaid red points show the locations of churches in the Philadelphia Archdiocese (i.e. Roman Catholic), based addresses on

Note how clusters of points show us where there are towns. If you enlarge the map, you can see the boundaries of the archdiocese (Philadelphia and surrounding counties, but not NJ).


This shows a closer view:


Here is the same as the above; in this render green dots represent Roman Catholic churches, and red are the churches that closed in 2013 (I’d like to extend this back a couple years, but haven’t found a good data set so far).


Finally, I’ve included one very high resolution image of all churches (click to enlarge)



These begin to provide a small window into broader trends – many of the closed churches are in centralized areas.

In fact, many churches were built long in the past, codifying the state of various decades in large edifices. In future renders, I will show how this shows us immigration trends from the past (through names of Saints used on Catholic churches), migration within areas of the city (with data provided by the Philadelphia Presbytery), and look at how different religions are distributed across the same area (e.g. by mapping mosques and synagogues).

2 Replies to “Maps of Philadelphia Churches, Part 1”

  1. this is really cool, gary. Thank you for sharing. One thing that might be helpful to know is that churches like the one you attend are often referred to by the kind of heat that was available at the time–we would call it a coal-era church, meaning that it was built during an era before car transportation, when people lived, worked, and shopped in their neighborhood and didn’t leave it. There was no need for a parking lot, so these churches often overbuilt their space and then suffered when people started to drive to churches based on programming rather than location.

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