The borough is located along Darby Creek 5 miles (8.0 km) southwest of Center City Philadelphia.

Darby was settled in 1682 by seven Quaker families led by abolitionist and fair trade advocate John Blunston.

In this early stage of provincial government, Blunston became a strong proponent for the rights of the Assembly.

In 1685 Blunston was appointed to a committee that argued against the Provincial Council's practice of enacting laws without legislative approval.

In the same year, Blunston led the Assembly in their attempt to impeach Chief Justice Nicholas More.

In addition to Blunston's service in the Assembly, he served as a Provincial Councilor starting in 1700 and ending in 1723.

The Darby Friends Burial Ground is the oldest Cemetery in Pennsylvania in continuous use, opened in 1682.

Samuel Gorman, a 17-year-old black boy, was sent to jail for the alleged murder of William E. Taylor.

It has a humid subtropical climate (Cfa) and average monthly temperatures range from 33.6 °F (0.9 °C) in January to 78.3 °F (25.7 °C) in July.

[17] The city is also home to Blessed Virgin Mary (BVM), a parochial school affiliated with the Roman Catholic Archdiocese of Philadelphia.

[19] Darby Borough is in Pennsylvania's 5th Congressional district, currently represented by Democrat Mary Gay Scanlon.

In the Pennsylvania legislature, Darby is represented by Democrat Joanna E. McClinton in the 191st House District.