Bowdoin College, Special Collections at the Bowdoin College Library. The Mosher Press publications, organized in order by Hatch number, take up 34 linear feet of over 600 books. There are also two folders of ephemera related to Thomas Bird Mosher, including two of his extensive law books catalogues which show Mosher’s early ability to produce book catalogues.
Colby College, Special Collections at the Merton Leland Miller Library. There are 40 linear feet of books and other material from the Mosher Press, including books from Mosher’s library. Some of the select items include fifteen pieces of correspondence to and from Mosher, a 30-page notebook recording some of the books in Mosher’s home library, various checklists of the Mosher books including the Sheean Typescript (often referred to by Hatch and Bishop) a catalogue of a collection of Mosher books assembled by Oliver Sheean, newspaper clippings, a journal of Mosher’s Old World Series tracing the books behind the Mosher’s reprints, and numerous pieces of memorabilia related to Mosher (including illustrations, specimen book covers, and photographs).
Dartmouth College, The Rauner Special Collections Library. In addition to a modest selection of over 200 Mosher imprints, the special collections contains a manuscript box of holograph and typed material, including letters from Mosher to his wife, correspondence relating to the settlement of his estate, a manuscript catalogue of his library (the first page of which is pictured on p.  of the Hatch Check List…), the preliminary designs for Mosher’s edition of William Blake XVII Designs to Thornton’s Virgil (pictured on p.  of the Hatch Check List…), two typescript lists of his publications, legal and business papers, and photographs. There are also letters from poet Robert Frost to Mosher, purchased from the 1948 sale of Mosher’s library. Volumes I & V (1886 & 1890) of Mosher’s copy of The Century Guild Hobby Horse are also located at Dartmouth.
Kalamazoo College, Special Collections at the Upjohn Library. There are about 550 volumes in the collection which was assembled by Robert Athol Huston, labor attorney, poet and bibliophile. To highlight this collection, the library sponsored a Mosher books exhibition called “A Modern Love of Literature” from June 7-August 30, 1991.
Maine State Library, Special Collections Department. The 36 linear feet of books includes the 14 series in both Van Gelder and Japan vellum states, in their original boxes.
Portland Public Library, Special Collections in the Portland Room, has a collection of about 40 linear feet. Mosher’s assistant, Flora Lamb, provided many of these books to the library.
University of Louisville, Rare Book Department at the University of Louisville Library. This is the Kenneth H. Shanks Collection (Shanks was the author of the 1976 article on Mosher in the University of Louisville’s Library Review). There are over 1,100 volumes covering 50 linear feet, and the collection includes some very rare items (e.g., one of three copies of Verses and a Dream). There are also a few notes and letters to or from Mosher.
University of South Florida, Special Collections at the Library of the University of South Florida. The library has over 615 of the Mosher books. The basic core of the collection was privately formed by Thomas Dreier.
Yale University. The primary Mosher collection is part of the Zeta Collection of the Yale University Library System. There are also various individual items at the Beinecke, Mudd and Sterling libraries. The collection takes about 21 linear feet, and most of the books in this collection carry the bookplate of Andrew Squire of Cleveland, OH, and are marked as the Gift of Edward B. Greene Yale 1900. Others were the gift of Miss Marie Louise Royael and Mrs. Julia Royael McCay, 1912.