This collection contains a series of letters addressed to a Mrs. Bessie McAllen as well as a composition book full of Charles Gilliss' notes on the McAllen family history. The letters to Mrs. McAllen give an overview of everything Gilliss has found on her family line. The first letter dates 1932, and Gilliss informs her that on his initial perusal of the family line, he has found seven Levin Gilliss' living in the 1700s. Throughout the 1932 letters, he researches more into each Levin and begins to piece together their lives. In a 1934 letter, Gilliss informs Mrs. McAllen that both ancestors of hers, Levin Gilliss, and Captain Thomas Gilliss, were in the same company and battalion of MD troops in the Revolutionary War. It is evident in the 1934 letters that Mrs. McAllen has asked Gilliss to research her family line in order to solidify her standing in the D.A.R. The composition book that accompanies these letters are the personal notes and findings from Gilliss on the family line. The first half of the book includes handwritten copies of deeds and wills that Gilliss has found from the McAllen family members. The second half is mainly notes connecting certain family members, along with their birth and death dates. The very last pages of the notebook include more wills of McAllen ancestors.

Charles Gilliss was born in 1873 in the state of Illinois. Gilliss was college educated, and could read and write. He lived in Haymarket, VA for most of his life, and died there in 1955 at the age of 83. At the age of 34, Gilliss married his wife Esther, but they never had any children. However, the Gilliss family had a cook, Dola Thomas (black), age 15, that lived with them on their farm. Gilliss was an agent for the Rust & Gilliss Insurance Company.