Mapping New Philadelphia, IL

Michael Minn

29 December 2020

New Philadelphia was a town in western Illinois that was founded in 1836 by Frank McWorter (1777 - 1854), a former slave who was able to save enough money to purchase his own freedom and that of his wife and 13 family members in Kentucky. McWorter's official town plan included 144 lots and is believed to be the earliest known town founded and registered in a state by an African American in the antebellum United States. The racially integrated town later became a stop on the underground railroad for slaves escaping to Canada. The city population peaked around 160 immediately after the US Civil War.

In 1869, the new Hannibal and Naples Railroad bypassed New Philadelphia and instead built a station four miles to the west in Barry, IL. New Philadelphia subsequently began to lose population and the town land reverted to agriculture. A portion of the town was legally dissolved in 1885 and the only modern morphological remnants are a handful of residual gravel streets.

In 1996, a group of local residents formed the New Philadelphia Association to preserve the memory of the site. A major NSF-funded archaeological excavation of the site was conducted 2003. The town was added to the National Register of Historic Places in 2005 and designated a National Historic Landmark in 2009.

For further information:

2020 Map

Below is a map showing the original lot boundaries and street names, along with some notable sites around the original town plat.

New Philadelphia, IL in 2020

Interactive Map

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2020 Parcels

Below is a map showing parcel numbers and ownership. Also included are the boundaries of the town from the georeferenced 1872 plat as well as the town boundary included in the 2005 National Historic Landmark nomination as UTM coordinates.

New Philadelphia, IL Parcels as of 29 December 2020

1872 Plat

The original town plat consisted of 144 60' x 120' lots arranged in 20 blocks. Each block contained four groups of two lots separated by 15' alleyways, making each block 255' x 255' except for four half-blocks of four lots on the west edge of the town. The town had five east-west streets and five north-south streets. The streets were 60' wide except for Broad Street, which was 80' wide.

1872 Plat of New Philadelphia, IL

1939 Aerial Imagery

The street names and historic locations overlaid on a historic aerial image of the area taken on 21 August 1939 show some residual town elements that still existed in the middle 20th century, including:

New Philadelphia, IL, 1939

Geospatial Data Files

The following geospatial data files were created based on tract survey data provided by the New Philadelphia Association, as well as a plat of a survey performed by Jeff C. Hart that was completed on 28 August 2017.

Conversions of survey directions to NAD83(2011) / Illinois West (ftUS) (EPSG 6457) State Plane northings and eastings was done in R using the sf and rgdal libraries. The point of beginning for the georeferencing of the 1872 plat is the Northwest corner of the Northeast Quarter of Section 27, Township 4 South, Range 5 West of the Fourth Principal Meridian, Pike County, Illinois. This point was calculated as South 89 degrees 08 minutes 56 seconds East along the North line of Section 27 a distance of 2674.32 feet from the northwest corner of Section 27 (IL040040S0050W0SN270) as provided by the Bureau of Land Management PLSS Navigator service.

The point of beginning is 2072418 E, 1104915 N in the State Plane system, or, 39.698199, -90.972837 in WGS 84 latitude and longitude. Based on Hart's plat, this point is 16.43 feet west of the westernmost lot property line and in the centerline of North Street, which places it 30 feet north of the northernmost lot property line.

Survey directions were only given for the New Philadelphia Association and Archaeological Conservancy parcels. The Philadelphia Land Trust parcels were derived from the boundaries of the New Philadelphia Association and Archaeological Conservancy parcels. You should consult with a professional surveyor if you need definitive legal boundaries.

There is a misalignment between the georeferenced plat and the remaining roadways that may be due to migration of the road over the past two centuries, a misalignment of the original roads relative to the original plat, and / or a misalignment of the georeferenced plat to the original plat.



Boundaries (NHL and georeferenced plat)


Notable historic locations around the town


A georeferenced historic aerial image of the area taken on 21 August 1939 and downloaded from Illinois State Geological Survey's Illinois Historical Aerial Photography website.

A georeferenced National Agricultural Imagery Program (NAIP) aerial image (3.75 x 3.75 minute) from 18 November 2015 downloaded from the USGS National Map.

The R script used to convert the survey directions into the geospatial files above.