Tredyffrin Township, Chester County, Pennsylvania

According to the United States Census Bureau, the township has a total area of 19.9 square miles (52 km²), of which 19.8 square miles (51 km²) is land and 0.04 square miles (0.10 km²), or 0.15%, is water.

At the 2010 census, the township was 83.3% non-Hispanic White, 3.3% Black or African American, 0.1% Native American, 9.8% Asian, and 1.4% were two or more races. 2.2% of the population were of Hispanic or Latino ancestry.[4]

As of the census[5] of 2000, there were 29,062 people, 12,223 households, and 7,834 families residing in the township. The population density was 1,464.9 people per square mile (565.6/km²). There were 12,551 housing units at an average density of 632.6 per square mile (244.3/km²). The racial makeup of the township was 90.88% White, 2.84% African American, 0.11% Native American, 5.12% Asian, 0.01% Pacific Islander, 0.29% from other races, and 0.74% from two or more races. Hispanic or Latino of any race were 1.20% of the population.

There were 12,223 households, out of which 29.0% had children under the age of 18 living with them, 55.9% were married couples living together, 6.2% had a female householder with no husband present, and 35.9% were non-families. 30.1% of all households were made up of individuals, and 9.1% had someone living alone who was 65 years of age or older. The average household size was 2.36 and the average family size was 2.99.

In the township the population was spread out, with 23.3% under the age of 18, 4.7% from 18 to 24, 30.1% from 25 to 44, 27.2% from 45 to 64, and 14.7% who were 65 years of age or older. The median age was 40 years. For every 100 females there were 89.9 males. For every 100 females age 18 and over, there were 86.7 males.

The median income for a household in the township was $82,258, and the median income for a family was $105,183 (these figures had risen to $90,915 and $121,809 respectively as of a 2007 estimate[6]). Males had a median income of $76,393 versus $46,124 for females. The per capita income for the township was $47,584. About 2.2% of families and 3.7% of the population were below the poverty line, including 4.6% of those under age 18 and 2.8% of those age 65 or over.

Tredyffrin is governed by a seven-member Board of Supervisors. Four members are elected from the township at-large, while three members are elected from specific districts, though all supervisors are treated equally once on the Board.

Party registration as of July 2010 were 45% Republican, 39% Democratic, and 16% Independent and third parties. In the 2008 Presidential election, Tredyffrin voters gave 58% of its votes to Democratic candidate Barack Obama over John McCain, a significant change from previous elections. Mitt Romney vastly improved upon John McCain's performance, but still fell short as Barack Obama carried the township with 52% of the vote in the 2012 Presidential election. Party registration as of December, 2019 stands at 43% Democratic, 39% Republican, 18% Independent and third parties.

On 13 March 1684, William Penn decided to set aside a portion of Pennsylvania for the Welsh to settle in. This area, known as the "Welsh Tract", was surveyed in 1684 and included several modern-day townships, including Tredyffrin. Although the Welsh Tract was originally meant to be a self-ruling municipality, it was divided between Chester County and Philadelphia when that county was created in 1685, and the Welsh subsequently submitted to the authority of Chester County. In 1707, Tredyffrin was incorporated as a township. This name comes from the Welsh tre(f), which means "town", joined to dyffryn, which means "wide, cultivated valley". Tredyffrin was quick to develop into a thriving township. In 1710, the first mill in Tredyffrin was started by Thomas Jerman on what is now North Valley Road. Swedesford Road, one of the first roads in the township, was created by 1718.

As the population of the township grew, with 30 resident landowners in 1722 and 83 in 1774, churches sprung up to meet the demand by religious residents. In 1710, the Baptist minister Hugh Davis moved to the Great Valley from Britain and, there being several Baptist families in this area, the Great Valley Baptist Church was formed on 22 April 1711. The church originally met in Radnor. However, there were enough members of this Baptist church that by 1722, a log building was erected in Tredyffrin to serve the congregation.

As Tredyffrin includes part of Valley Forge National Historical Park, there are many Revolutionary War-related sites in the township, especially the park and houses where various generals were quartered.

Development in the township was sparked in the 19th century by construction and advertisement of the "Main Line" railroad service, which terminated in Paoli, which straddles the western border of the township.

Tredyffrin-Easttown school district was unusual for the area in being integrated during the early part of the century.[7] In the 1932, the district planned to segregate after building a new school, and African-Americans in the township boycotted the school system for two years in protest (the "School Fight"). In 1934 a negotiated settlement was reached whereby the schools remained integrated, and helped kill school segregation in Pennsylvania.

During the Cold War, a Nike anti-aircraft missile site was active in the township.

County Bridge No. 171, Cramond, Cressbrook Farm, Federal Barn, Great Valley Mill, Greenwood Farm, David Havard House, Lafayette's Quarters, Maj. Gen. Lord Stirling Quarters, Strafford Railroad Station, Valley Forge National Historical Park, Joseph Walker House, Van Leer Cabin and Wetherby-Hampton-Snyder-Wilson-Erdman Log House are listed on the National Register of Historic Places. In addition, the Wharton Esherick Museum is listed as a National Historic Landmark; it was built starting in 1926.[8]

Other notable buildings are:

• Diamond Rock octagonal 1-room schoolhouse, built 1818
• Seven colonial log houses and cabins
• Knox Covered Bridge in Valley Forge Park
• Revolutionary war sites: Quarters of Major General William Alexander, Lord Stirling; Quarters of Major General Marquis de Lafayette; Quarters of Brigadier General Anthony Wayne; Quarters of General Charles Cornwallis, and a number of other generals.[9]
• Old Eagle School, built in 1788

The rocks of Tredyffrin were laid down in the upper Paleozoic, meaning that they are primarily metamorphic. Limestone is often at the surface in the Great Valley, so many limestone kilns were created in the 18th century. Mine owner William Rennyson sold the fizzy water from his Howellville limestone quarry as "Tredyffrin Water" around 1900.[10] The northern edge of the township is a ridge of quartzite and sandstone (the Cambrian Chickies Formation) including Valley Forge Mountain (or Mount Misery), which was mined for quartz in the 18th century through the mid-19th century.

• Futhey, J. Smith, and Gilbert Cope. History of Chester County, Pennsylvania, with Genealogical and Biographical Sketches. Philadelphia: Louis H. Everts, 1881. ISBN 0-7884-0206-4
• "Geologic Map of Pennsylvania". 2000. Commonwealth of Pennsylvania, Department of Conservation and Natural Resources, Bureau of Topographic and Geologic Survey. 16 December 2002.
• "History of Tredyffrin Township". Tredyffrin Township, Chester County, PA. 16 December 2002.
• "Limestone and Dolomite Distribution in Pennsylvania". 2000. Commonwealth of Pennsylvania, Department of Conservation and Natural Resources, Bureau of Topographic and Geologic Survey. 16 December 2002.
• "Relating common solutions: two libraries by Mitchell/Giurgola." Architectural Record. August 1977. Volume 162. p. 93-98. ISSN 0003-858X.

Wikimedia Commons has media related to Tredyffrin Township, Chester County, Pennsylvania.

• Tredyffrin Township official website
• Tredyffrin-Easttown School District
• Tredyffrin Historical Society