The St. Louis Mercantile Library has broad holdings of particular interest to researchers of the history of St. Louis, Western Expansion, Western Art, railroads, and inland waterways.  Processed collections can be browsed from this website, and many have digital content such as finding aids or scanned images of documents available on their individual pages.

Collections are available for in person viewing during scheduled hours, but visitors must follow the posted reading room procedures.  Photography is allowed in the reading room under conditions stated in the library's rules concerning cameras.  Images may also be purchased, with discounts for members, according to the posted images price list.  All library materials are subject to copyright

The library staff welcome inquiries, but patrons are encouraged to take advantage of the Reference Assistance program available to them.  There are research guides which may also be useful.