Materials in the Ernst Bacon Collection span his entire ninety-one year life. They include five series: Music, Writings, Correspondence, Iconography, and Miscellaneous materials. The bulk of materials are found in the Music, Correspondence, and Writings series.

The Music Series contains holographs, copyist manuscripts, and photoduplications of Ernst Bacon's music. Among these are his manuscripts for songs, solo instrumental pieces, and small ensembles with or without voice or voices. There is also a section of untitled holographs and photocopies of sketches and music workbooks with holographic annotation. Works are arranged alphabetically by title and cross-referenced when appropriate. There are also 30 pages of undeveloped titles sketches, which come from what Ernst Bacon called his woodpile, these have been alphabetized and foldered together.

The Writings Series consists of two subseries, poetry and prose. Both subseries contain published and unpublished works written by Ernst Bacon and arranged alphabetically by title. Included among the Prose subseries are many of his letters to various editors. These are included here because of the highly expository nature of the writing, which is more like prose than typical correspondence. The Collection also contains many notebooks which Bacon used for his prose writings. Although music is not the main emphasis of these materials, there are some musical jottings.

The Correspondence Series, is divided into two subseries, Family and General. The Family Correspondence Subseries contains all correspondence received by Ernst Bacon from his family. It also includes letters written by Ernst Bacon to family members. All correspondence files are arranged alphabetically by author and in chronological order therein. All correspondence written to family members by Ernst Bacon is filed under the addressee in chronological order, with the exception of the correspondence of Ellen, Peggy, and Paul Bacon. Letters of Ellen or Peggy to Ernst Bacon have been separated from letters of Ernst Bacon to them and then filed chronologically. Letters of Ernst Bacon's son, Paul, includes materials from and about his estate.

The bulk of the correspondence is found in the General Correspondence Subseries. As mentioned above letters to the editor, which are usually found in this subseries, have been listed in prose subseries of the Writing series for the aformentioned reason. Contained here are letters from notable musicians and writers including Ernest Bloch, G. Whitefield Chadwick, and Vincent Persichetti, Carl Sandburg, and Thornton Wilder; there are also letters from everyone else who were not family.

The Iconography Series contains photographs, artwork, and posters. Among the photographs are portraits of Ernst Bacon alone, Bacon with his father and mother and various family members, etc. Some of the art is in Ernst Bacon's hand. A notable piece of art in the collection is the original caricature of Ernst Bacon by the artist Sotomayor. This series also contains posters advertising performances given by Ernst Bacon from 1918.

The Miscellaneous Series comprises academic material dating from Ernst Bacon's undergraduate years, two appointment books, a Who's Who certificate, clippings from 1920-76, financial/legal papers dating from 1907-77, lists of various kind, some dated and some undated, a radio interview with Ernst Bacon, programs, publicity releases, and writings by others.