Free and fee-based:
Check out FamilySearch’s Montana Online Genealogy Records for a comprehensive list of links to both free and fee-based databases.
Free:
Explore these free online databases for Montana:
Montana Naturalization Records, 1868-1999
Montana, Beaverhead County Records, 1862-2009
Montana, Big Horn County Records, 1884-2011
Montana, Cascade County Records, 1880-2009
Montana, Chouteau County Records,1876-2011
Montana, County Births and Deaths, 1840-2004
Montana, County Marriages, 1865-1950
Montana, County Naturalizations, 1856-1979
Montana, Death Index, 1860-2007
Montana, Flathead County Records, 1871-1981
Montana, Granite County Records, 1865-2009
Montana, Judith Basin County Records, 1887-2012
Montana, Lake County Records, 1857-2010
Montana, Rosebud County Records
Montana, Sanders County Records, 1866-2010
Montana, Sweet Grass County Records, 1887-2011
Montana, Teton County Records, 1881-2012
Montana, Toole County Records, 1913-1960
Montana, Yellowstone County Records, 1881-2011
Montana State Death Registry Index Pre-1954 & 1954-2002
Missoula Public Library Newspaper Vital Records Index
McKenney’s Pacific Coast Directory for 1883-1884 (includes Montana)
Pacific Coast Business Directory 1867 (includes Montana)
University of Montana Digital Collections
History of Washington, Idaho, and Montana, 1845-1888
Montana State Prison Records, 1869-1974
Progressive Men of the State of Montana, vol 1
Progressive Men of the State of Montana, vol 2
Western States Marriage Records Index
Online digital newspaper collections listed in Genealogy’s Star:
On Granny's Trail 