The majority of the transportation corporations included in this series are railroad and street railway companies. These corporation files contain official documents pertaining to the corporate status and/or operations of each company, such as: incorporations (charters) and amendments, annual reports, agreements and leases, name changes, mergers, sales, route maps, etc. While some of the filings date to the early nineteenth century (e.g. documents from as early as 1816 in the Delaware and Raritan Canal file), most date from after 1875, when corporations engaged in business in New Jersey were required by law to file with the Secretary of State annual reports providing the names and terms of the company's directors, officers, etc. (see P.L. 1877, chap. 68).

Box 46 of this series contains a card index to the corporation files, which not only records the years of annual reports received by the Secretary of State, but also reports individual filings for each company. A list of company names is provided following the box contents list below. The company name list provides the file number if a file exists for a company; in cases where a card exists without an actual file, "--" has been used in place of the file number. In either case, the card-file index should be consulted for possible additional information not found in the file itself (such as a charter citation or a Secretary of State's map reference).