Letters exchanged by members of the Herford family and friends pertaining mostly to family and personal matters. Included are letters from Beatrice Herford, Rev. Brooke Herford, Helen Herford, Jack Herford, Susan Whitney Herford, Oliver Herford, William Herford, Dolly Whitney, Harvey W. Louther, Sue Larabie Cunningham, and Kula Thuss. Letters were written from various locations in Massachusetts, Montana, England, and elsewhere. Included are letters written by Jack Herford while serving in the Spanish American War and related documents. For letters between Helen Herford and her business partner, Helen Underwood Wellington see series two, ranch letters. Many of the letters are undated, and the identification of many writers is unclear. The letters have been loosely arranged by the name of the supposed writer or recipient.

Letters created or collected by Helen Brooke Herford pertaining to the establishment and operation of her dude ranch, the Swinging H, near Limestone, Montana. Included are: letters to and from her partner, Helen Underwood Wellington, that were written before and during the ranch establishment; letters from various guests who stayed at the ranch or requested information regarding its facilities; notes and memorandum regarding employees; personal letters of Helen Brooke Herford written after the closing of the ranch in 1937.

Financial records, promotional essays, diaries and subject files pertaining to the operation of the Swinging H ranch. Papers include: bank statements and tax records; promotional essays written by Helen Brooke Herford for submission to dude ranch magazines; brief memoranda diaries from 1930 and 1934; subject files pertaining to the ranch automobiles, livestock, legal matters, facility construction, and the development of women's pants by Levi Strauss and Company in 1934.

674 individually numbered prints, six albums, and multiple negatives of images taken by Helen Brooke Herford, the Herford family, or commercial photographers of a wide variety of subjects and people. Included are images of: The Herford family and residences; Montana communities; Yellowstone National Park; Montana lakes, rivers, and mountains; vacation and leisure activities; ranch life on both the Herford and Swinging H ranches. The photographs have been arranged in alphabetical order based on broad subject headings. Photograph albums and negatives have been stored in separate containers. The negatives for prints found in the photograph albums are collected in small booklets bearing the same volume number. Loose negatives which have no corresponding prints have been gathered in similar subject headings as the numbered prints in boxes 4 and 5.