The Wayne State Library System launched its library mapping application in February 2010, designed to help locate materials in the five WSU libraries. The system works within the catalog to show the location of materials, as well as provides a web form for use at the reference desk. Developed using PHP and MySQL, it requires only minimal effort to update using a unique call number overlay mechanism. In addition to mapping shelved materials, the system provides information for any of the over three hundred collections held by the WSU Libraries. Patrons can do more than just locate a book on a shelf: they can learn where to locate reserve items, how to access closed collections, or get driving maps to extension center libraries. The article includes a discussion of the technology reviewed and chosen during development, an overview of the system architecture, and lessons learned during development.