Nearly 2 Million Pennsylvanians Live Within a Kilometer of Oil & Gas Wells

By Matt Kelso, Manager of Data & Technology

In October 2014, the FracTracker Alliance performed an analysis showing an estimated 1.2 million people lived within a half mile of oil and gas wells in Pennsylvania. We have now updated the analysis, but this time, the unit of measure is one kilometer (0.62 miles).

PA Population Within 1km of Active Oil and Gas Wells

This map shows the estimated population within one kilometer of active oil and gas wells in PA – a total of nearly 2 million Pennsylvanians. To access the full set of tools and details about how the map was made, click here for the full screen version of the map.


To get as complete a picture as possible of the oil and gas industry in PA, we queried the spud date report to show all wells that were listed as being spudded between January 1, 1800 and November 12, 2015. We used the former date because it appears to be a default for unknown spud dates, and the latter being the date that the data were downloaded for the analysis. Altogether, this yielded 203,887 oil and gas wells throughout the state, but 74,900 (37%) of these lacked location coordinates. All of those missing latitude and longitude data were classified as conventional wells, and many of them were fairly old. We then filtered out wells that were reported as not being drilled, as well as those that were permanently plugged, either by the operator, or by the PA Department of Environmental Protection (PADEP). The resulting set, which we refer to as “active” oil and gas wells, included 106,970 wells, of which 9,042 (8%) are defined as unconventional wells by the state.

To obtain an estimated population, we used the Census Tract level of detail, using official 2010 population figures. We calculated the area within 1 kilometer of active wells in three categories – conventional, unconventional, and all oil and gas wells. The population was then estimated by comparing the area inside the 1 km zone to the entire Census Tract, multiplying that ratio to the population of that tract, and repeating the process for each of the three datasets.

This area calculation was performed in Albers Equal Area projection optimized for the Great Lakes Basin area.  Every method of flattening an area of a globe on the map will lead to some type of distortion, but this projection prioritizes area over other factors, and is therefore appropriate for this type of analysis.


An additional year of drilling activity, a more comprehensive date range, and the slight increase of the radius distance has had a significant effect on the estimated population near wells. The 2014 analysis yielded an estimated 1,264,576 within a half-mile of wells, while the current analysis has the figure at 1,965,837, an increase of 55%. Below is a table showing differences between the two analyses:


This chart shows summaries of the current analysis of population within 1 km of wells in PA and an October 2014 version, showing population within a half-mile of wells.

One thing you will notice in this figure is that simply adding up the number of people who live in areas near unconventional and conventional drilling will not get you to the 1,965,837 figure we’ve presented. This is because some people live within the specified distance of both types of wells.

Additionally, it is impossible to say how many people live near the oil and gas wells that lack location data, as we obviously can’t map these wells. The majority of these wells may be in the areas that are already represented in the buffer zones, or they may extend that distance significantly.

Conventional and unconventional wells in PA

Over 1.2 Million Pennsylvanians Within 1/2 Mile of a Well

Aging well in McKean County, PA. Source:

One of the potentially troubling aspects of oil and gas development is that there are usually people who live in the vicinity of the wells. Pennsylvania now has over 8,000 active unconventional wells; there are any number of issues that can occur with these modern, industrial-scale sites, including road degradation, contaminated water, and health impacts, among others. In addition, there are over 93,000 of the smaller, conventional wells in operation throughout the Commonwealth. While these garner far less attention than their unconventional counterparts, they are also prone to producing similar impacts, not to mention that since many of them are older wells, they not only have potentially been subject to deterioration and occasional neglect, but were constructed during a period with less stringent requirements than are currently expected.

Petroleum engineers are now capable of drilling horizontally for tens of thousands of feet. For the most part, however, this technology is employed to maximize production, rather than to ameliorate impacts on people who live near the product. But who are these people? To help to answer this question, the FracTracker Alliance calculated the number of people living in a half-mile radius around active wells in the state.

More than 1.2 million Pennsylvanians live within the impact area.

Of the 93,754 wells that have been drilled in the state since 1950 that have not yet been plugged, the Pennsylvania DEP only has location data for 79,118 of them. All but one of the 14,636 missing locations are for wells that are categorized as Conventional. While one must presume that there is some overlap in coverage within the half-mile zone, the extent of this region – and therefore the population that lives within it – cannot be determined.

Fig. 1. PA Populations Near Oil and Gas Wells. Click here to access written description and additional map tools.

To maximize the reliability of our calculations, this map was created using a custom Albers equal-area projection centered on Pennsylvania. A half-mile buffer around each well type was created, and the resulting layer was clipped to Census tract data. The ratio of the smaller clipped area to the full Census tract area was calculated, and that ratio was then multiplied by the population totals from the 2010 Census to obtain our population estimates of the half-mile zone. The area in the study area is larger than six states, while the calculated population is larger than that of eight states.

Of the 79,118 active oil and gas wells in PA for which location data are available, we determined the area and estimated the population within a half mile radius. Note that some regions are with a half-mile of both conventional and unconventional wells.

Fig. 2. Number of people in PA near oil and gas wells (79,118 active wells for which location data are available). Note that some regions are with a half-mile of both conventional and unconventional wells.

The county most impacted, in terms of area, for unconventional wells is Bradford, with 353 square miles (See Figure 2). Washington County had the most people living in the zone, however, with 20,566. For conventional wells, the drilling landscape is the largest in Indiana County, affecting 761 square miles, while Erie County has the most people in the half-mile zone, with 212,900. When considering all wells together, the numbers are almost identical to conventional wells. Indiana County leads with 762 square miles, while the drill zone in Erie County represents 211,903 people, or 76% of the county’s population in 2010.