The Associated Factory Mutual Fire Insurance Companies comprised twenty-eight mutual insurance firms that specialized in industrial fire insurance. The collection consists of seventy original hand-colored plans and maps primarily depicting textile mills, paper products factories and foundries in New England and New York.

Account books were maintained by individuals and business as a way to keep track of financial transactions. This collection includes thirty-eight account books from twenty-five different businesses and individuals in the Delaware, Maryland, and Pennsylvania area, with one additional account book from San Francisco County, California.

The Dallin Aerial Surveys Company produced aerial photographs for newspapers, businesses, municipalities, and private individuals. The company was founded in 1924 by Colonel J. (John) Victor Dallin (1897-1991), a Royal Flying Corps-trained pilot who served in World War One. During WWI he became involved in aerial photography on a reconnaissance mission during the latter stages of the war. This collection consists of over 13,000 aerial photographs primarily of the Mid-Atlantic region taken between 1925 and 1941. The company made vertical and oblique aerial photographs of factories, private estates, schools, country clubs, towns, airports, rivers, and many other sites and some news events of the day. The subject with the largest number of views is the city of Philadelphia.

Frank A. Weer (1932-2019) was an employee of the Reading Company and an enthusiastic photographer of all things related to railroads, specifically in Pennsylvania. Fascinated by trains from a young age, Weer spent time taking photographs of the passing rolling stock. He developed his own photographs, and over time, he established a vast collection of photographic prints of steam locomotives and other rolling stock, as well as the railroad tracks and structures with which the railroad was affiliated. The Reading Company, where Weer worked for thirteen years, was an influential railroad company that served the economic development of the Greater Philadelphia area for over 100 years. Before it became a booming passenger railroad, the Reading Company began transporting anthracite coal. The passenger "ridership" of the Reading Company reached its peak in the 1950s. The company went bankrupt in 1971, and the passenger services were taken over by the South Eastern Pennsylvania Transportation Authority by 1974. This collection documents the construction and expansion of the Reading Railroad and the company's tangible property and human resources throughout the twentieth century. The collection consists of negatives (glass plate and film), photographic prints, and color slide transparencies. The creator established a chronological order, which has been maintained. The collection is arranged into five series: Structures and objects, Passenger stations, Rolling stock, People, and Frank A. Weer's personal slides.

James Henry Yeager (1911-1986) was the industrial photographer for the Bethlehem Steel Corporation for thirty years, between 1946 and 1976. The first half of this collection contains photographs taken by James H. Yeager during his tenure at Bethlehem Steel as industrial photographer. The second half the this collection consists of photos and slides taken by Yeager while traveling in Pennsylvania, New York, and New England, and to a lesser degree Washington, DC and the southern United States.

Stephen Onion (d. 1754) was an important ironmaster in the Chesapeake colonies during the early 18th century. The document is a three-page biographical sketch of Stephen Onion, copied from more extensive genealogical notes. The sketch includes several quotations from Onion's letters, which are not otherwise identified.

The Pennsylvania Indemnity Corporation was an automobile insurance company located in Philadelphia, Pennsylvania. This item is a road atlas containing 32 pages of maps of the northeastern United States. Published by Rand McNally and Company.

The Pennsylvania Railroad Company was the largest railroad in the United States in terms of corporate assets and traffic from the last quarter of the nineteenth century until the decline of the northeast's and midwest's dominance of manufacturing. These records provide nearly comprehensive coverage of corporate matters for the entire time span and reasonably complete coverage of the functional departments from 1920 to 1950, with less coverage from 1893 to 1920 and from 1950 to 1968.