Tyndall Public Library was one of the last of the twenty-five Carnegie libraries built in South Dakota. Unique among the state's Carnegie libraries, Tyndall’s facility is influenced by the Prairie School and Craftsman styles rather than the more typical Classical Revival. The rectangular brick building rests on a raised concrete basement foundation and is topped with a red-clay–tiled hipped roof. A wide, overhanging eave is supported by large decorative brackets. The centered main entrance projects slightly from the front of the building, and the wide doorway is topped with a curved transom. Sioux City architectural firm Beuttler and Arnold designed the library, which was built by Goetz Construction Company, also of Sioux City.
Tyndall Public Library is one of only a few of the South Dakota Carnegie libraries still used for its original purpose. Much of the wood trim and original furnishings, including wood tables, chairs, and bookcases, remain intact. In 2018, the Bon Homme Heritage Museum began using the library basement to catalog and archive its collection.