Great Valley is a west-to-east valley

Valley

In geology, a valley or dale is a depression with predominant extent in one direction. A very deep river valley may be called a canyon or gorge.The terms U-shaped and V-shaped are descriptive terms of geography to characterize the form of valleys...

 through the center of Chester County, Pennsylvania

Chester County, Pennsylvania

-State parks:*French Creek State Park*Marsh Creek State Park*White Clay Creek Preserve-Demographics:As of the 2010 census, the county was 85.5% White, 6.1% Black or African American, 0.2% Native American or Alaskan Native, 3.9% Asian, 0.0% Native Hawaiian, 1.8% were two or more races, and 2.4% were...

, USA. It is also sometimes referred to as Chester Valley, and both names are in use throughout the region. The valley stretches from the Schuylkill River

Schuylkill River

The Schuylkill River is a river in Pennsylvania. It is a designated Pennsylvania Scenic River.The river is about long. Its watershed of about lies entirely within the state of Pennsylvania. The source of its eastern branch is in the Appalachian Mountains at Tuscarora Springs, near Tamaqua in...

 in Montgomery County

Montgomery County, Pennsylvania

Montgomery County is a county located in the U.S. state of Pennsylvania, in the United States. As of 2010, the population was 799,874, making it the third most populous county in Pennsylvania . The county seat is Norristown.The county was created on September 10, 1784, out of land originally part...

 in the east, southwesterly through Chester and Lancaster

Lancaster County, Pennsylvania

Lancaster County, known as the Garden Spot of America or Pennsylvania Dutch Country, is a county located in the southeastern part of the Commonwealth of Pennsylvania, in the United States. As of 2010 the population was 519,445. Lancaster County forms the Lancaster Metropolitan Statistical Area, the...

 counties. The valley is most distinct in central Chester County, although traces of it can be followed almost the entire distance between the Delaware

Delaware River

The Delaware River is a major river on the Atlantic coast of the United States.A Dutch expedition led by Henry Hudson in 1609 first mapped the river. The river was christened the South River in the New Netherland colony that followed, in contrast to the North River, as the Hudson River was then...

 and Susquehanna

Susquehanna River

The Susquehanna River is a river located in the northeastern United States. At long, it is the longest river on the American east coast that drains into the Atlantic Ocean, and with its watershed it is the 16th largest river in the United States, and the longest river in the continental United...

 rivers.

Valley Creek

Valley Creek

Valley Creek is a tributary of the Schuylkill River in eastern Chester County, Pennsylvania, United States, flowing through an area known as the Great Valley....

 flows along the base of eastern Great Valley, towards the Schuylkill River. A second creek, also named Valley Creek, flows westward from Frazer

Frazer, Pennsylvania

Frazer, Pennsylvania is a community in East Whiteland Township, Pennsylvania, United States....

 into the East Branch Brandywine Creek

East Branch Brandywine Creek

The East Branch Brandywine Creek is a tributary of Brandywine Creek in Chester County, Pennsylvania in the United States.-Course:The creek starts in Suplee near Honey Brook, and joins the West Branch Brandywine Creek in Lenape. From its source, the creek flows east, then southeast, passing through...

. Beaver Creek flows eastward along the northern side of the valley from around Thorndale into the East Branch Brandywine Creek. Multiple branches of both the Brandywine and Octoraro

Octoraro Creek

Octoraro Creek is a tributary of the Susquehanna River, joining it above the Susquehanna's mouth at Chesapeake Bay. The Octoraro rises as an East and West Branch in Pennsylvania. The East Branch and Octoraro Creek form the southern half of the border between Lancaster and Chester counties until...

 creeks cross the valley.

Communities

Significant communities in the Great Valley include, from east to west, King of Prussia

King of Prussia, Pennsylvania

King of Prussia is a census-designated place in Upper Merion Township, Montgomery County, Pennsylvania, United States. As of the 2010 census, its population was 19,936. The community took its name in the 18th century from a local tavern named the King of Prussia Inn, which was named after...

, Valley Forge

Valley Forge, Pennsylvania

The Village of Valley Forge is an unincorporated settlement located on the west side of Valley Forge National Historical Park at the confluence of Valley Creek and the Schuylkill River in Pennsylvania, United States. The remaining village is in Schuylkill Township of Chester County, but once...

, Chesterbrook

Chesterbrook, Pennsylvania

Chesterbrook is a census-designated place in Chester County, Pennsylvania, United States. The population was 4,589 at the 2010 census.-Geography:Chesterbrook is located at ....

, Exton

Exton, Pennsylvania

Exton is a census-designated place in West Whiteland Township, Chester County, Pennsylvania, United States. Its population was 4,842 at the 2010 census. The Exton Square Mall is located within Exton along with several other shopping centers, making Exton the major shopping district in Chester...

, Downingtown

Downingtown, Pennsylvania

Downingtown is a borough in Chester County, Pennsylvania, west of Philadelphia. As of the 2010 census it had a population of 7,891. Downingtown was settled by English and European colonists in the early 18th century and has a number of historic buildings and structures.-History:The town was...

, Thorndale

Thorndale, Pennsylvania

Thorndale is a census-designated place in Chester County, Pennsylvania, United States. The population was 3,407 at the 2010 census. Thorndale is the commercial and administrative center of Caln Township. The community's main street is Business U.S. Route 30...

, Coatesville

Coatesville, Pennsylvania

Coatesville is the only city in Chester County, Pennsylvania, United States. The population was 13,100 at the 2010 census. Coatesville is approximately 39 miles west of Philadelphia....

, Parkesburg

Parkesburg, Pennsylvania

Parkesburg is a borough in Chester County, Pennsylvania, United States. The population was 3,593 at the 2010 census. The Zip code is 19365.-History:...

, and Atglen

Atglen, Pennsylvania

Atglen is a borough in Chester County, Pennsylvania, United States. The population was 1,406 at the 2010 census.-Geography:Atglen is located at ....

.

Transportation

Both the Pennsylvania Turnpike

Pennsylvania Turnpike

The Pennsylvania Turnpike is a toll highway system operated by the Pennsylvania Turnpike Commission in the Commonwealth of Pennsylvania, United States. The three sections of the turnpike system total . The main section extends from Ohio to New Jersey and is long...

 and US 202 follow the eastern portion of the valley. U.S. Route 30

U.S. Route 30

U.S. Route 30 is an east–west main route of the system of United States Numbered Highways, with the highway traveling across the northern tier of the country. It is the third longest U.S. route, after U.S. Route 20 and U.S. Route 6. The western end of the highway is at Astoria, Oregon; the...

 enters the valley around Malvern

Malvern, Pennsylvania

Malvern is a borough in Chester County, Pennsylvania, United States. The population was 2,998 at the 2010 census. The main road through the borough is King Street, although the borough is also bordered by Paoli Pike on the south, and is near US 30 on the north. The primary cross street is Warren...

 and serves as the main thoroughfare in the valley as far west as Coatesville

Coatesville, Pennsylvania

Coatesville is the only city in Chester County, Pennsylvania, United States. The population was 13,100 at the 2010 census. Coatesville is approximately 39 miles west of Philadelphia....

, where PA 372

Pennsylvania Route 372

Pennsylvania Route 372 is an east–west highway in York, Lancaster, and Chester counties. Its western terminus is at Pennsylvania Route 74 in Lower Chanceford Township north of Delta and west of Holtwood, and its eastern terminus is at Pennsylvania Route 82 in Coatesville.-York and Lancaster...

 becomes the main road along the valley to its western end. The Great Valley is also served by Amtrak

Amtrak

The National Railroad Passenger Corporation, doing business as Amtrak , is a government-owned corporation that was organized on May 1, 1971, to provide intercity passenger train service in the United States. "Amtrak" is a portmanteau of the words "America" and "track". It is headquartered at Union...

 and SEPTA rail service for much of its length.

This Great Valley is near and parallel to, but distinct from, the Great Appalachian Valley

Great Appalachian Valley

The Great Valley, also called the Great Appalachian Valley or Great Valley Region, is one of the major landform features of eastern North America. It is a gigantic trough — a chain of valley lowlands — and the central feature of the Appalachian Mountain system...

.