The Pennsylvania Power & Light Co. is an energy utility and transmission distributer based in Allentown, Pennsylvania. Arising from a business merger, the company was founded on June 4, 1920, and soon after began providing energy to eastern and central Pennsylvania. Renamed PP&L Corporation circa 1995, the company continues to operate as an energy provider within northeastern Pennsylvania. The collection consists primarily of photographs that depict sites of various PP&L subsidiaries and those directly operated by the company. It is a resource that can be used for insight into PP&L's early operations and eastern and central Pennsylvania industrial development. Images within this collection range from 1920 to 1973. Researchers interested in electric power transmission and its development within the state of Pennsylvania would find this collection useful.

Pennsylvania Power & Light traces its origins to the various water and gas light companies that began operating in the eastern part of the state during the mid-nineteenth century. The records of the Pennsylvania Power & Light Company predecessor and subsidiary companies document the history of the gas and electric utility industry in eastern Pennsylvania in the years between 1853 and 1957. The collection includes both the administrative and operating records of more than 1100 companies that merged to form the PP&L system.

Pennsylvania Power & Light Company formed in 1920 through the consolidation of eight electric utilities companies serving central and eastern Pennsylvania. The collection primarily includes corporate papers documenting the company’s acquisition of various competing electric companies in the early-to-mid twentieth century by way of franchise building, market research and corporate communications, hydroelectric development through studies and surveys on Pennsylvania’s waterways, and material documenting the company’s various power plants in central eastern Pennsylvania. Financial and accounting records of the Pennsylvania Water & Power Company, which PP&L acquired in 1955, are also included.

The Philadelphia Electric Company was incorporated under the laws of Pennsylvania on October 31, 1929, as a merger of The Philadelphia Electric Company (incorporated in Pa. on October 27, 1902), the Philadelphia Suburban-Counties Gas & Electric Company, and three other small utility companies. It is the primary gas and electric company for Philadelphia, its surrounding counties and Cecil and Harford Counties in northeastern Maryland. Their records consist of microfilm copies of the minute books of about 150 of the predecessor companies of the Philadelphia Electric Company.

Thomas Parke Hughes (1923-2014), was one of the leading historians of technology of his era. This collection consists of files relating to the research and production of Professor Hughes' two prize-winning books, Networks of Power, and Elmer Sperry: Inventor and Engineer. Also included are Elmer Sperry's original desk diaries.