|Borough of Darby|
|Elevation||79 ft (24.1 m)|
|Area||0.8 sq mi (2.1 km2)|
|- land||0.8 sq mi (2 km2)|
|- water||0.0 sq mi (0 km2), 0%|
|Density||12,624.5 / sq mi (4,874.3 / km2)|
|- summer (DST)||EDT (UTC-4)|
Darby is a borough in Delaware County, Pennsylvania, United States, along Darby Creek 5 miles (8.0 km) southwest of downtown Philadelphia. It has a public library founded in 1743 and a cemetery more than 300 years old. The Quakers lived there early in the colonial era. Darby was settled about 1654, and was incorporated on March 3, 1852. In 1900, 3,429 people made their homes there, in 1910, 6,305, and in 1940, 10,334 residents of Darby existed. The population was 10,687 at the 2010 census. There is speculation, according to local historians, that the name "Darby" is related to "Derby" derived from the English town of Derby, in the county of Derbyshire. One explanation states that the Darby Creek closely resembled the English River Derwent, the main body of water that flows through Derby. British immigrants named the town in the new world thus.
Birthplace of comedian and actor, W.C. Fields, born in 1880 at the Arlington Hotel, then located at 832 Main Street.
Darby is home to the 5th oldest all volunteer Fire Department and 2nd oldest Free Library in the United States.
Darby Borough is a distinct municipality from the similarly named, nearby municipality of Darby Township.
Darby is located at .(39.918312, -75.258360)
According to the United States Census Bureau, the borough has a total area of 0.8 square miles (2.1 km2), all of it land.
As of the census of 2000, there were 10,299 people, 3,405 households, and 2,393 families residing in the borough. The population density was 12,624.5 people per square mile (4,849.3/km²). There were 3,999 housing units at an average density of 4,902.0 per square mile (1,883.0/km²). The racial makeup of the borough was 36.37% White, 60.00% African American, 0.14% Native American, 0.87% Asian, 0.07% Pacific Islander, 0.51% from other races, and 2.04% from two or more races. Hispanic or Latino of any race were 0.95% of the population.
There were 3,405 households out of which 41.3% had children under the age of 18 living with them, 34.1% were married couples living together, 30.0% had a female householder with no husband present, and 29.7% were non-families. 25.6% of all households were made up of individuals and 9.0% had someone living alone who was 65 years of age or older. The average household size was 2.88 and the average family size was 3.45.
In the borough the population was spread out with 33.4% under the age of 18, 7.7% from 18 to 24, 28.2% from 25 to 44, 17.1% from 45 to 64, and 13.6% who were 65 years of age or older. The median age was 32 years. For every 100 females there were 85.7 males. For every 100 females age 18 and over, there were 75.3 males.
The median income for a household in the borough was $26,938, and the median income for a family was $30,065. Males had a median income of $35,507 versus $22,451 for females. The per capita income for the borough was $16,990. About 35.5% of families and 20.6% of the population were below the poverty line, including 27.6% of those under age 18 and 11.1% of those age 65 or over.
Darby is a relatively urban place, with almost twice the population density of nearby Darby Township. The Pennsylvania State Police reported that the crime rate (per capita)in 2011 compared to the per-capita rate for Delaware County as a whole was six times for violent crimes (homicide, robbery, and assault, not including sex crimes), twenty-four times for property crimes (including arson), but only two times for drug offenses (not including alcohol offenses).
William Penn School District serves Darby.
- Park Lane Elementary School (K-6)
- Walnut Street Elementary School (K-6)
- Penn Wood Middle School (7-8)
- Penn Wood High School, Cypress Street Campus (9-10) (Yeadon)
- Penn Wood High School, Green Ave Campus (11-12) (Lansdowne)
In addition to these public institutions, there is in Darby the school known as Blessed Virgin Mary (BVM), a parochial school affiliated with the Roman Catholic Church.
Notable people 
- Negro league baseball executive John Drew.
- Actress Monica Horan is from Darby, Pennsylvania. She is best known for her role as Amy MacDougall on Everybody Loves Raymond.
- 19th Century House of Representative John James Pearson was born at or near Darby.
- Early American Botanist John Bartram, the father of the even more famous traveler and botanist William Bartram, was born in Darby. He was also buried in Darby at the Friends Cemetery at 13th and Main Street. His botanical garden exists nearby and is the oldest surviving botanical garden in the US.
- Entertainer W.C. Fields was born in Darby.
- Sports Broadcaster Chris Wheeler.
- John Patrick Cardinal Foley, former Grand Master of the Equestrian Order of the Holy Sepulchre of Jerusalem and former President of the Pontifical Council for Social Communications, lived in retirement at the Villa St. Joseph in Darby, a home for retired, infirm, and convalescent priests of the Roman Catholic Archdiocese of Philadelphia.
- Leo Burt, placed on FBI 'Ten Most Wanted' list for his role in the Sterling Hall bombing, was born in Darby.
- see New Sweden
- "US Gazetteer files: 2010, 2000, and 1990". United States Census Bureau. 2011-02-12. Retrieved 2011-04-23.
- "American FactFinder". United States Census Bureau. Retrieved 2008-01-31.
- [ucr.psp.state.pa.us/ucr/Reporting/RUAware/RUAwareCountyUI.asp "Pennsylvania Uniform Crime Reporting System"] Check
- 483 vs 4168, 881 vs 19521, and 101 vs 2442, reported crimes respectively, for borough population of 10687 and county population of 558,979 as given in their report.
- "Experience America’s first botanic garden".