History Now, the online journal of the Gilder Lehrman Institute, devoted an edition to the American West in 2006. One of the essays explores "the myth of the frontier," of which “Home on the Range” is part.
The National Archives has posted a wonderful collection of photos at this site.
If you are interested in the history of Kansas, you will appreciate this site sponsored by the University of Kansas. Among the postings is an article on the crash of the buffalo population.