The Family History Library has useful directories for the years 1868 and 1879 on Family History Library film 1377090. The library has some directories from the 1930s to 1980s for larger cities in Montana, such as Billings, Bozeman, Butte, Great Falls, Helena, Kalispell, and Missoula.
- Distant Cousins for Montana
- Ancestry.com ($)
- US City Directories This web site identifies printed, microfilmed, and online directories and their repositories.