Tredyffrin Township municipal offices are located at 1100 Duportail Road, Berwyn, PA 19312.
Tredyffrin Township  is a developed suburb of Philadelphia, located in the Great Valley of eastern Chester County. The Township encompasses 19.8 square miles and is situated along the US Route 202 corridor between King of Prussia, PA and West Chester, PA. Tredyffrin's location is easily accessible from many major transportation corridors, including the Pennsylvania Turnpike, the Schuylkill Expressway (I-76), the Blue Route (I-476), and US Route 422 and is the location of three train stations along the Main Line commuter rail corridor into Philadelphia.
Tredyffrin Township is home to more than a dozen historic resources that have been listed on the National Register of Historic Places. Among these are:
Cramond, circa 1886, designed by NYC architectural firm McKim, Meade and White; built for Daniel S. Newhall, a Pennsylvania Railroad executive. Built on a site so that the front windows would have a commanding view of the Strafford Station.
Cressbrook Farm, original portion of the house was built by John Harvard in 1745; major addition in 1825; used during Washington's 1777-1778 Valley Forge encampment as the headquarters of Brigadier general Louis Lebique Duportail.
Wharton Esherick Studio circa 1926, is a National Historic Landmark.
Federal Barn (Cressbrook Farm), circa 1792 and 1840; original structure built by John H. Moor; thought to be the only Pennsylvania bank barn that was "signed" by the builder.
Great Valley Mill, circa 1859; grist mill constructed by Joseph F. Jeanes; built on the site of an earlier mill (circa 1710) that probably helped supply flour to Washington's Troops at Valley Forge.
Greenwood Farm, circa 1790; 1798 tax records show the farm, owned by James Davis, having a stone house 30 x 35 ft, a stone barn, 55 x 30 ft, and a tenant house 15 x 18 ft. By the mid-nineteenth century it had become a "gentleman's farm" for a succession of wealthy owners.
David Harvard House, circa 1766; served as quarters for Major General Charles Lee and Colonel William Bradford during Washington's Valley Forge encampment, 1777-1778. In the 1880s, J Cassatt, president of the Pennsylvania Railroad, purchased this (along with several other farms) for a country estate on which to raise horses.
Roughwood (Lamb Tavern 1812-1866; Roughwood since 1887); the only surviving building from the village of Glassley. Going from tavern to boarding house it ended up as summer home for a succession of notable Pennsylvanians, including: Civil War Hero Albert S. Ashmead, publisher Peter Zeigler, banker Thomas A. Biddle, and steamship line owner Colonel Michael Dallet. Worked-on 1928-1930 by architect R. Brognard Okie;
Major General Lord Stirling Quarters circa 1739; known as Homestead Farm, circa 1880, then Echo Valley Farms 1926-1973; the house evolved from the original one room, one story plan built by Henry John, through a series of rambling additions.
Portion of Valley Forge National Historic Park
Joseph Walker House, circa 1757; served as headquarters for General Anthony Wayne during Washington's Valley Forge encampment; built by Joseph Walker, of the third generation of Walkers in Tredyffrin Township. Exemplary of the expanding farmhouse, having seen three major additions.
Wetherby et. al. Log House, circa 1700; Whitehead Weatherby sold the house and accompanying land in 1772; it is unusual in its use of round logs, other materials (shale), a herringbone design in the chinking, and stone additions to the original log structure.
"Few townships in Pennsylvania are as rich in history as Tredyffrin Township, which is located at the easternmost edge of Chester County, Pennsylvania. In the center of the Township lies the rich and fertile Great Valley, beginning at Valley Forge and running west toward Coatesville. The earliest settlers were Welsh, and to them, the Township owes its name. Ten or Tre is the Welsh word for town or township, and Dyffrin means a wide cultivated valley; from these words comes the compound tre yr dyffrin, or Tredyffrin, meaning a township in a wide cultivated valley.
"The Township had its beginning in 1682 when a group of Welsh Quakers went to William Penn in England and purchased, at a price of ten cents an acre, forty thousand acres of land in southeastern Pennsylvania. Penn promised the Quakers that here they could enjoy their customs and language in a little "barony" of their own. This land was originally known as the Welsh Tract and included within its boundaries parts of nine subsequent townships in four counties.
By 1707, Tredyffrin's population was large enough for it to be incorporated as a township. After they had cleared their land and established farms, the most pressing requirements for the early settlers became a mill to grind grain, a meetinghouse for their spiritual needs, and a market where they could sell produce. An example of meeting these needs was the construction of the Great Valley Mill, one of Tredyffrin's first mills. It was in operation by 1710, possibly even earlier, and was built by Thomas Jarman, a noted preacher and miller, on 300 acres of land by Valley Creek (it is now located on North Valley Road in Malvern." 
Nearby Towns: Bridgeport Boro • Conshohocken Boro • East Norriton Twp • Easttown Twp • Haverford Twp • Lower Providence Twp • Marple Twp • Newtown Twp • Norristown Boro • Plymouth Twp • Radnor Twp • Upper Merion Twp • Upper Providence Twp • West Conshohocken Boro • West Norriton Twp • Whitpain Twp •