Virtual reference is a service that makes particular sense in a state like Montana. The fourth-largest state by geographic area but 44th by population in the U.S., it has about one library per 11,392 residents. Montana's libraries, including the libraries of Montana Tech of the University of Montana, where the author currently serves as a reference librarian and assistant professor, have a long history of collaborating to provide services. Interlibrary loans, home delivery of books, shared catalogs, shared statewide resources, and other collaborative projects have all made it from idea to reality in Montana. So it was natural that virtual reference would be considered as yet another form of resource sharing--the sharing of librarians' expertise instead of books or databases. In this article, the author discusses Montana's virtual reference service, Ask Montana (http://askmontana.org), that is staffed by the Montana Virtual Reference Cooperative, a multitype group of 21 public, school, and academic libraries. By planning, organizing, and seeking help when necessary, the author asserts that it is possible to maintain and grow a service that utilizes volunteers and a minimal budget. The collaboration that has been worked out in Montana is the outgrowth of several years of conversations and negotiations and has resulted in a cooperative and service that can concentrate on growing and sustaining virtual reference in the state.