Tredyffrin Township (Welsh: Tre (town) + Dyffryn (valley)) is a township located in eastern Chester County, Pennsylvania, United States. The population was 29,332 at the 2010 census. Originally settled in the late 17th century, Tredyffrin is bounded by Delaware and Montgomery counties. It includes on its northern boundary a small part of Valley Forge National Historical Park, where George Washington encamped during the American War of Independence. Tredyffrin and the entire Great Valley region also have many limestone deposits.
Unincorporated communities within Tredyffrin Township include Chesterbrook, Strafford, a portion of Paoli, and a portion of Wayne. Tredyffrin is bordered by Easttown, East Whiteland, Willistown, Charlestown, Upper Merion, Radnor and Schuylkill townships.
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.
As of the census 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). 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.
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 tref, 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. In 1714, the Great Valley Presbyterian Church was started in Tredyffrin. It was the first Presbyterian church in Chester County. A church building was built in 1720 and was used for 73 years. Also in 1714, the Quaker Haverford Monthly Meeting (which was established in April 1684) voted to allow its members that lived in the Great Valley to hold a meeting every other month in Tredyffrin, which was called the Valley Meeting. There was also an Anglican church, built in 1700.
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. 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 Harvard House, Lafayette’s Quarters, Maj. Gen. Lord Stirling Quarters, Strafford Railroad Station, Valley Forge National Historical Park, Joseph Walker House, 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.
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.
– 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. 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.
Students in Tredyffrin Township attend schools in the Tredyffrin/Easttown School District.
High school students in Tredyffrin Township attend Conestoga High School.
Private schools in Tredyffrin Township include:
– Delaware Valley Friends School (Paoli address)
– Devon Preparatory School (grades 6 -12, Devon address)
– Woodlynde School (Strafford address)
– Heritage School (preschool, Wayne address)
– Vanguard School (ungraded special education, Paoli address)
Tredyffrin Township Libraries operates the Tredyffrin Library and the Paoli Library.