In the course of our work, we've come across some interesting resources for teaching about three often overlooked Montana communities: the Hmong, who settled in Missoula and the Bitterroot Valley, Mexican-Americans of the Yellowstone Valley, and Hutterites, whose colonies dot central and eastern Montana.
Hmong and Mexican MontanansThe Hmong are one of Montana's most recent immigrant groups. Check out the Hmong Missoula to learn more about their history and culture.
Some years ago, with funding from the NEH, the Montana Historical Society produced a DVD titled Montana Mosaic: Twentieth Century People and Events. The DVD features 12 short films--chapter 5, "Ethnic Migrations" includes information on both the Hmong and Mexican migrations. We donated copies to each public Montana middle and high school library. You can find the user guide for chapter 5 here.
The best essay I know about on Mexican Americans' Montana experiences is Laurie Mercier's very readable "Creating a New Community in the North: Mexican Americans of the Yellowstone Valley," first published in Stories from an Open Country: Essays on the Yellowstone River Valley (Billings, 1995). The Montana Historical Society Press reprinted it in Montana Legacy: Essays on History, People, and Place (Helena, 2002).