The Nicodemus Historical Society Collection dates from 1880 to 2015 and is divided into series named according to the donor of the material: Nicodemus Historical Society, and individual citizens of Nicodemus who have donated materials from their life, family, and the community of Nicodemus. Each series includes personal papers of individuals and families, as well as collected articles relating to Nicodemus or national events of interest to those individuals. The Nicodemus Historical Society series consists chiefly of the organization's records.

The collection's photographic material located at RH MS-P 1425 is organized into series that mirror the collection's mansucript materials, divided by individual donor or photographs from the Nicodemus Historical Society or related entities. The material has been organized alphabetically by last name of donor, followed by a series of "Various people," who only contributed one or a few folders, and lastly by photographs relating to Nicodemus or the Nicodemus Historical Society. Photographs at this location have consistently been organized alphabetically by last name of subject, followed by subjects identified by only first names, followed by unidentifed subjects, followed by non-human subjects.

The Nicodemus Historical Society photographic addition located at RH PH 508 is arranged in three series: Events, People, and Nonhuman Subjects. Within People are eight subseries: Children, Families, Groups, Men, Men and Women, and Women. Arrangement is chiefly alphabetical by name or, if name is unavailable, by subject; where arrangement is by names, the last name is used where possible. Where possible, identification has been given on photographs. Unidentified photographs have been described in-depth on their housing. Where only partial identification is available, a question mark has been included within the labeling (e.g. "? Smith"). Where multiple, identified prints of the same size are housed in one folder, subjects of individual prints are noted. Where a subject appears in photographs across multiple categories, an effort has been made to provide cross reference information; this information is included in the description as "See also" notes. Photograph size is given in inches. Unless noted with a "b/w" (to indicate black and white), images are in color. The term "image" has been used to indicate photographs with differing subjects (e.g. 2 images include a photo of subject A and one of subject B). The term "copies" has been used to indicate multiple prints of the same image. Where possible, photographers are indicated in the collection cescription.

Oversize textual materials are located at RH MS Q429, RH MS R419, and four large folders at RH MS R420. Four oversize photographs are housed at RH PH 508(f).

Wherever possible throughout the finding aid, processing staff have included identifying information provided by the Nicodemus Historical Society, including collection numbering information (i.e. "PC 102.6," "NHS #: PC-122-PH-158").