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Delaware County, Pennsylvania
Seal of Delaware County, Pennsylvania
Map of Pennsylvania highlighting Delaware County
Location in the state of Pennsylvania
Map of the USA highlighting Pennsylvania
Pennsylvania's location in the U.S.
Founded September 26, 1789
Seat Media
Largest City Chester
 - Total
 - Land
 - Water

191 sq mi (495 km²)
184 sq mi (477 km²)
6.8 sq mi (18 km²), 3.5%
 - (2015)
 - Density

3,065/sq mi (1,183/km²)
Named for: Delaware River
Pennsylvania Historical Marker
Designated: October 3, 1982

Delaware County, colloquially referred to as Delco, is a county located in the U.S. state of Pennsylvania. With a population of 562,960, it is the fifth most populous county in Pennsylvania, and the third smallest in area. The county was created on September 26, 1789, from part of Chester County and named for the Delaware River.

Its county seat is Media. Until 1850, Chester City was the county seat of both Delaware County and, before that, of Chester County.

Delaware County is adjacent to the city-county of Philadelphia and is included in the Philadelphia–CamdenWilmington, PA–NJDEMD Metropolitan Statistical Area. Delaware County is the only county covered in its entirety by area codes 610 and 484.


Chester Courthouse 1724
The old Chester Courthouse, built in 1724.

Delaware County lies in the river and bay drainage area named "Delaware" in honor of Thomas West, 3rd Baron De La Warr, Governor of the nearby English colony of Virginia. The land was "discovered" and explored by Henry Hudson in 1609, and over the next several decades it was variously claimed and settled by the Swedes, the Dutch, and the English. Its original human inhabitants were the Lenni-Lenape tribe of American Indians.

Once the Dutch were defeated and the extent of New York was determined, King Charles II of England made his grant to William Penn in order to found the colony which came to be named Pennsylvania. Penn divided his colony into three counties: Bucks, Philadelphia, and Chester. The riverfront land south of Philadelphia, being the most accessible, was quickly granted and settled. In 1789, the southeastern portion of Chester County was divided from the rest and named Delaware County for the Delaware River.


Bartrams Bridge NRHP
Bartram's Covered Bridge, built 1860 west of Newtown Square, crosses Crum Creek into Chester County.

According to the U.S. Census Bureau, the county has a total area of 191 square miles (490 km2), of which 184 square miles (480 km2) is land and 6.8 square miles (18 km2) (3.5%) is water. It is the third-smallest county in Pennsylvania by area.

Delaware County is roughly diamond- or kite-shaped, with the four sides formed by the Chester County boundary to the northwest, the boundary with the state of Delaware (a portion of the "Twelve Mile Circle") to the southwest, the Delaware River (forming the border with the state of New Jersey to the southeast, and the city of Philadelphia and Montgomery County to the east and northeast.

The lowest point in the state of Pennsylvania is located on the Delaware River in Marcus Hook in Delaware County, where it flows out of Pennsylvania and into Delaware. The highest point in Delaware County is 500 feet at two points southeast of Wyola in Newtown Township [1].

Newlin Mill, built 1704, on the west branch of Chester Creek, near Concordville.

Waterways in Delaware County generally flow in a southward direction and ultimately drain into the Delaware River. The waterways are, from west to east: the Brandywine River (forming a portion of the county's western boundary with Chester County), Chester Creek, Ridley Creek, Crum Creek, Muckinipates Creek, Darby Creek and Cobbs Creek (forming a portion of the county's eastern boundary with Philadelphia). Crum Creek was dammed in 1931 near Pennsylvania Route 252 to fill Springton Lake (also known as Geist Reservoir), an approximately 391-acre (1.58 km2) drinking water reservoir maintained by Aqua America, the county's largest lake.

Adjacent counties

Delaware County is one of four counties in the United States to border a state with which it shares the same name (the other three are Nevada County, California, Texas County, Oklahoma, and Ohio County, West Virginia).

National protected area

John Heinz National Wildlife Refuge
  • John Heinz National Wildlife Refuge (part)

State protected area

2,600 acres (11 km2) of the county are occupied by the Ridley Creek State Park.

Climate and weather

Weather chart for Media, Pennsylvania
temperatures in °F
precipitation totals in inches
source: The Weather Channel


Historical population
Census Pop.
1790 9,469
1800 12,809 35.3%
1810 14,734 15.0%
1820 14,810 0.5%
1830 17,323 17.0%
1840 19,791 14.2%
1850 24,679 24.7%
1860 30,597 24.0%
1870 39,403 28.8%
1880 56,101 42.4%
1890 74,683 33.1%
1900 94,762 26.9%
1910 117,906 24.4%
1920 173,084 46.8%
1930 280,264 61.9%
1940 310,756 10.9%
1950 414,234 33.3%
1960 553,154 33.5%
1970 600,035 8.5%
1980 555,007 −7.5%
1990 547,651 −1.3%
2000 550,864 0.6%
2010 558,979 1.5%
Est. 2015 563,894 0.9%
U.S. Decennial Census
2013 Estimate

As of the 2010 census, the county was 71.1% White non-Hispanic, 19.7% Black or African American, 0.2% Native American or Alaskan Native, 4.7% Asian, 0.0% Native Hawaiian, 2.0% were two or more races, and 0.9% were some other race. 3.0% of the population were of Hispanic or Latino ancestry.

As of 2000, there were 550,864 people, 206,320 households, and 139,472 families residing in the county. The population density was 2,990 people per square mile (1,155/km²). There were 216,978 housing units at an average density of 1,178 per square mile (455/km²). The racial makeup of the county was 80.32% White, 14.52% African American, 0.11% Native American, 3.29% Asian, 0.02% Pacific Islander, 0.56% from other races, and 1.19% from two or more races. 1.52% of the population were Hispanic or Latino of any race. 24.6% were of Irish, 17.5% Italian, 10.1% German and 6.7% English ancestry.

There were 206,320 households out of which 31.50% had children under the age of 18 living with them, 50.80% were married couples living together, 12.90% had a female householder with no husband present, and 32.40% were non-families. 27.60% of all households were made up of individuals and 11.60% had someone living alone who was 65 years of age or older. The average household size was 2.56 and the average family size was 3.17.

In the county, the population was spread out with 24.80% under the age of 18, 8.90% from 18 to 24, 28.80% from 25 to 44, 21.90% from 45 to 64, and 15.60% who were 65 years of age or older. The median age was 37 years. For every 100 females there were 91.20 males. For every 100 females age 18 and over, there were 86.90 males.

The median income for a household in the county was $50,092, and the median income for a family was $61,590. Males had a median income of $44,155 versus $31,831 for females. The per capita income for the county was $25,040. About 5.80% of families and 8.00% of the population were below the poverty line, including 10.00% of those under age 18 and 7.10% of those age 65 or over.


Delaware County is bisected north to south by Blue Route Interstate 476, which connects I-76 just north of the extreme northern corner of the county to I-95, which parallels the Delaware River along the southeastern edge of the county.

Delaware County is home to SEPTA's 69th Street Terminal in Upper Darby, and is served by the Norristown High Speed Line (P&W), two Red Arrow trolley lines (Routes 101 and 102), four Regional Rail Lines (the Airport Line, Wilmington/Newark Line, Media/Elwyn Line, and Paoli/Thorndale Line), and a host of bus routes.

The western portion of Philadelphia International Airport is located in Delaware County, and the county hosts some airport-related commerce such as Philadelphia's UPS terminal and airport hotels.

Major highways

  • I-95
  • I-476
  • US 1
  • US 13
  • US 30
  • US 202
  • US 322
  • PA 3
  • PA 252
  • PA 352
  • PA 452
  • PA 320
  • PA 420
  • PA 291
  • PA 491
  • PA 261


Dam on Ridley Creek in Ridley Creek State Park
Rose Tree Tavern 2013
Old Rose Tree Tavern in Rose Tree Park.

There is one Pennsylvania state park in Delaware County.

  • Ridley Creek State Park

County parks Include:

  • Clayton Park & Golf Course
  • Glen Providence Park
  • Kent Park/Dog Park
  • Rose Tree Park
  • Smedley Park
  • Upland Park


Map of Delaware County Pennsylvania With Municipal and Township Labels
Map of Delaware County, Pennsylvania with Municipal Labels showing Cities and Boroughs (red), Townships (white), and Census-designated places (blue).

Under Pennsylvania law, there are four types of incorporated municipalities: cities, boroughs, townships, and exactly one town. There are 49 municipalities in Delaware County:




Census-designated places

Census-designated places are geographical areas designated by the U.S. Census Bureau for the purposes of compiling demographic data. They are not actual jurisdictions under Pennsylvania law. Other unincorporated communities, such as villages, may be listed here as well.

Unincorporated communities

Population ranking

The population ranking of the following table is based on the 2010 census of Delaware County.

county seat

Rank City/Town/etc. Municipal type Population (2010 Census)
1 Chester City 33,972
2 Drexel Hill CDP 28,043
3 Ardmore (partially in Montgomery County) CDP 12,455
4 Yeadon Borough 11,443
5 Broomall CDP 10,789
6 Darby Borough 10,687
7 Lansdowne Borough 10,620
8 Woodlyn CDP 9,485
9 Collingdale Borough 8,786
10 Folsom CDP 8,323
11 Brookhaven Borough 8,006
12 Village Green-Green Ridge CDP 7,822
13 Glenolden Borough 7,153
14 Ridley Park Borough 7,002
15 Clifton Heights Borough 6,652
16 Folcroft Borough 6,606
17 Prospect Park Borough 6,454
18 Swarthmore Borough 6,194
19 Norwood Borough 5,890
20 Sharon Hill Borough 5,697
21 Media Borough 5,327
22 Boothwyn CDP 4,933
23 Aldan Borough 4,152
24 Linwood CDP 3,281
25 Upland Borough 3,239
26 Lima CDP 2,735
27 Morton Borough 2,669
28 East Lansdowne Borough 2,668
29 Colwyn Borough 2,546
30 Chester Heights Borough 2,531
31 Eddystone Borough 2,410
32 Marcus Hook Borough 2,397
33 Parkside Borough 2,328
34 Trainer Borough 1,828
35 Haverford College (partially in Montgomery County) CDP 1,331
36 Millbourne Borough 1,159
37 Chenyney University (mostly in Chester County) CDP 988
38 Rose Valley Borough 913
39 Rutledge Borough 784

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