The Lehigh Coal & Navigation Company was a major anthracite mining and transporting firm in eastern Pennsylvania between 1822 and 1954. This collection consists of one outbound letterpress copybook dating from 1844 to 1848 of Edwin A. Douglas (1805-1859), Chief Engineer & Superintendent; three outbound letterbooks of William Reed, Chief Clerk at Mauch Chunk, dating from 1852 to 1859; thirteen outbound letterbooks of George Ruddle (1828-1904), Chief Clerk, Treasurer, and Real Estate Agent, dating from 1860 to 1878; and four inbound letterbooks of George Ruddle dating from 1870 to 1874. The letterbooks contain the correspondence of some of the chief field officers at Mauch Chunk, much of it regular exchanges with the officers at the Philadelphia headquarters.

Lehigh Coal Mine Company was an unincorporated joint-stock company, established in 1792, with the intention of developing a deposit of anthracite coal discovered by Jacob Weiss (1750-1839) and others at what is now Summit Hill in Carbon County, Pennsylvania. The collection consists of documents relating to land ownership and governance of Lehigh Coal Mine Company.

Chartered in 1871, Reading Company was the holding company for the system of railroads, canals and coal mines assembled by the predecessor Philadelphia & Reading Railroad Company between 1833 and 1896. The collection consists of the corporate records of the Reading Company (1871-1976), the Philadelphia & Reading Railroad Company (1833-1896), the Philadelphia & Reading Railway Company (1896-1923), and 159 predecessors and subsidiaries.