Glenolden Borough municipal offices are located at 36 Boon Avenue, Glenolden, PA 19036; phone: 610-583-3221.
Glenolden is located in the lower Delaware River region, which was initially explored by the Dutch in the early 17th Century. The Lenni Lenape tribe of Native Americans inhabited the area then. In 1638, Swedish merchants sailed up the river to the present-day site of Wilmington, Delaware, and in 1643 established the first settlement of "New Sweden" on Tinicum Island. Swedish merchants officially claimed the Delaware River for the Swedish Crown. However, the Dutch, who had reestablished their presence in the area, eventually overran New Sweden. The Dutch controlled the region until 1664 when the English who also claimed the area, defeated them. On March 14, 1681, King Charles II of England granted the Province of Pennsylvania to William Penn as repayment for a debt owed to his father by the English Crown.
The original land grants given by Penn were subdivided and sold to individual farmers. John Knowles' family would eventually acquire much of the property in present-day Glenolden, owning most of the Borough by the 1770s. The large Knowles estate was divided throughout the years for inheritance or sold off as smaller farms. Development also included mills along the creeks in the late 1700s, including the Glenolden Mill.
With industrialization occurring in the late 1800s, conditions of city living were worsening while new perspectives on rural living became widespread. In 1872, the first rail lines by the Philadelphia, Wilmington, and Baltimore Railway Company (PWB) traversed the Borough, effectively opening the heretofore distant suburbs of Philadelphia. In 1885, the Baltimore and Ohio Railroad Company (B&O) established a route through Glenolden. A decade later, the Prospect Park Railway Company created another transportation route with a trolley line on Chester Pike, known as the "Annie Moore" or "Essy Moore." Land speculation followed in the wake of the railroads. The Glenolden Land Association, one of the first land speculators in Glenolden, began developing portions of the area in the 1870s. In 1903, a Philadelphia realtor began developing what is known as Glenolden Manor in the southwestern portion of the Borough. Henry J. Scott purchased a portion of the Knowles Estate in 1886 and laid out Scott and Llanwellyn Avenues and called the development "Llanwellyn." Scott continued to sell property in Llanwellyn until his death in 1932, when the remaining undeveloped property was given to the Borough, in lieu of back taxes, becoming the basis for Glenolden Park.
A second period of rapid growth in the Borough was due to the industrial and commercial development in Delaware County. H.K. Mulford Company, a major company in the production of smallpox and diphtheria toxins and serums, moved into Glenolden in 1898, purchasing a former estate and the lands of the Glenolden Mills. A portion of the Moore estate was sold to a greenhouse operation, the Robert Craig Company, in 1910. In the 1920s, the DuPont Auto Company and the Alloy Metal Wire Company moved into Prospect Park. Population increase led to the creation of additional subdivisions on former farms, including Glenolden Terrace in the 1920s, and areas that were plotted earlier had homes constructed on them in the 1920s through the 1940s.