The Ruth Cromer Weir papers date from 1805 to 1993 and measure 12 linear inches. The papers are arranged in four series: Personal, Professional, Photographs, and Artifacts.

Most of the materials in the Personal series (1805-1964) pertain to Weir's family history. The series includes genealogical information and family trees compiled by Lela Lundy Cromer, Cromer's mother, a diploma from the State University of Iowa earned by Weir's sister, Helen Cromer, and obituaries for Cromer's parents and grandparents. Two Bibles may also be found within the collection. One belonged to Mary Cromer, Weir's sister, and the other belonged to her mother's grandparents, Levi and Sarah Lundy. Information about family history is written in the back cover of the Lundy Bible, and several pages are marked with Quaker tracts.

The bulk of the Professional series (1920s-1960) is composed of Weir's published children's books. Other materials include a rough draft of a children's book and several feature articles written by Weir in the 1920s for the Des Moines Sunday Register on topics ranging from jazz to paternity battles. One article highlights the surprise election of a woman mayor and an all-female town council in the 1920s in Randalia, Iowa, where women had declined to vote; all but one of the women refused to take office.

The bulk of the items in the Photographs series (1880s-1993) date from the late nineteenth and early twentieth centuries. Several of the photographs have been identified as Weir's relatives.

A baby bonnet and lace tatting which Weir wore as an infant, as well as a hinged case with two framed tintypes, make up the collection's Artifacts series. The tintypes are not specifically identified, but a note indicates that they are of her relatives.