The Ola Babcock Miller papers measure 4.75 linear feet in 13 boxes. The papers are arranged in the following series: Family History, Personal, Correspondence, Politics, and Photographs.

The Family History series (1908 – 2006) comprises documents about Ola Babcock Miller, her husband and children and the larger Miller family. It is arranged into five sub-series: General, Alex Miller, Ola Babcock Miller, Ophelia Miller Gallup, and Barbara Miller Benson. The General sub-series concerns the history of the Miller family in Iowa. There are few original documents, but the genealogical and family memoir folders contain information about the family from the 1850s to the early 2000s. The Alexander Miller sub-series focuses on the life and career of Alexander Miller, Ola Babcock Miller's husband. It contains financial information in the form of tax returns and a business binder and some bulletins about his career as a Chautauqua lecturer. There is one copy of his newspaper, The Democrat, but the issue was published after his death.

The Ola Babcock Miller sub-series is the most substantial in this series. It deals with the life and legacy of Ola Babcock Miller. This includes the by-laws and history of the P.E.O. Sisterhood, a copy of "Remarkable Iowa Women" which includes a section on Miller, and several obituaries and tributes from newspapers across the state. One tribute, Ola Babcock Miller Day in Washington, Iowa occurred decades after her death and had an Ola Babcock Miller impersonator. The file includes photographs of the event. Information about Miller's daughters, Ophelia and Barbara can be found in the final two sub-series. Newspaper clippings cover Barbara Miller Benson's wedding announcement, and Ophelia Miller Gallup's antique store and homemaking skills. The University of Iowa folder in Ophelia Miller Gallup's sub-series contains dance cards and invitations from sororities, fraternities, and other organizations: Kappa Kappa Gamma, Delta Chi, Joy Love, Theta Sigma Phi and the YWCA.

The Personal series (1914 – 2002) contains materials saved and used by Ola Babcock Miller in her personal life. It covers her interests demonstrated by items like playbills and Chautauqua programs and promotions, along with activities like her membership in the Nineteenth Century Club. The folder titled "Personal items from box labeled Mother's things" holds a variety of papers including a birth announcement, a mounted check and a brief travel journal.

The Correspondence (1914 – 1937) series has professional and personal correspondence of Ola Babcock Miller and her family. It is largely arranged by correspondent beginning with the letters of Barbara Miller Benson and continuing with Ophelia Miller Gallup and Alexander Miller before beginning Ola Babcock Miller's correspondence. Gallup's correspondence in the 1910s focuses on her social life as a student at the University of Iowa and then on her home life.

The first few files of Ola Babcock Miller's correspondence cover her personal letters with her husband and daughters. After that, the folders focus on her time in office as Iowa's Secretary of State. Those folders labeled "Personal Correspondence" near the end of the series are maintained in Miller's original order and surprisingly have mostly to do with letters she received from constituents. Many of these letters are requests for jobs with the State of Iowa. This series also contains two folders that refer to Miller's membership in P.E.O, including her time as president of the organization. The bulk of these have to do with a 1928 controversy in which she revealed her support for presidential candidate Al Smith. This was interpreted by some as an endorsement from P.E.O, to the distress of some members.

The Politics series comprises of materials related to Miller's years as Iowa's Secretary of State. It has one sub-series Highway Patrol. There is little in the series about the day-to-day activities of the Office of the Secretary of state, but several folders with newspaper clippings about Miller and her election as well as drafts of speeches she gave for various organizations. Many of these speeches are incomplete and focus on highway safety.

The Highway Patrol subseries itself includes automobile accident reports put out by the state of Iowa, early driving license exams, and newspaper clippings about the development and successes of the Patrol. In 1936, Miller requested stories from members of the Highway Patrol about their experiences on the job. The folder, Highway Patrolmen reminiscences contains several letters detailing incidents they encountered on the highway from hitchhikers to cold weather emergencies.

The Photographs series (1930 – 2006) has original newspaper photo plates with pictures of Ola Miller, as well as the corresponding pictures in newsprint. They are followed by two photo essays span the lives of Ola Miller and Ophelia Miller in pictures.