Big Horn County, Montana Genealogy Records

Selected record inventories for Big Horn County, their listed years, and where to ask for access.

Selected inventory review: 2026-11-02. Selected newspaper catalog metadata checked for state and county attribution. Publication dates do not establish complete issue holdings or online access. Library of Congress newspaper directory

Formed
1913
County seat
Hardin
Blaine CountyCarbon CountyCarter CountyChouteau CountyCuster CountyDawson CountyFallon CountyFergus CountyGarfield CountyGolden Valley CountyJudith Basin CountyMcCone CountyMeagher CountyMusselshell CountyPark CountyPetroleum CountyPhillips CountyPowder River CountyPrairie CountyRichland CountyStillwater CountySweet Grass CountyTreasure CountyValley CountyWheatland CountyRosebud CountyYellowstone CountyBig Horn CountyCarbonCarterCusterFallonFergusGarfieldMeagherMusselshellParkStillwaterRosebudYellowstoneBig Horn
Big Horn CountyParent counties (search here for earlier records)Today's boundaries ยท U.S. Census Bureau

Listed record inventories

Selected holdings and indexes for Big Horn County, checked against the repository descriptions linked below. Date spans may contain gaps; an index is not a complete set of original records.

Newspapers

See the repository's descriptions and search options

Repository access note: Selected newspaper titles cataloged by the Library of Congress with explicit county geography. Priority is given to titles beginning by 1950; up to five later titles are included where no earlier dated title is listed for that county. Dates describe publication history, not the issues available at a library. Multiple format records with the same title, place and dates are grouped. The catalog may describe paper, microfilm or online resources. Open ends and the word Current reflect the catalog description; confirm present availability and exact holdings with the libraries listed on the linked record.

Sources: the catalogs and repository descriptions linked on the entries above. Selected inventories do not establish complete coverage of every record type or online access to original documents. Read the repository access note for source dates and limitations.

Where to find the records

  • Big Horn County official website

    Hours, addresses and phone numbers for the county clerk and recorder, the clerk of the district court and the Montana Historical Society, and any online record search the county offers.

  • The county clerk and recorder

    Deeds and other land records, and registered births and deaths.

  • The clerk of the district court

    Marriage licenses, probate (wills and estates), divorces and naturalizations.

  • The Montana Historical Society

    In Helena: county records, state records and newspapers.

  • Montana Historical Society Research Centerfree

    The state's historical society library and archives in Helena: county and state records, newspapers and photographs.

  • FamilySearch Catalogfree

    Search by place for "Montana, Big Horn" to find filmed and digitized records, many viewable free online with a FamilySearch account.

Offices change their hours and access rules; call before you visit.

Boundaries and parent counties

Formed from: Rosebud County, Yellowstone County

Check the parent counties for earlier records: Rosebud County, Yellowstone County

Yellowstone National Park (part)DawsonValleyCarbonParkSweet GrassCusterCascadeMeagherMusselshellFergusChouteauBlaineRosebudYellowstoneBig HornBig HornRosebudYellowstoneDawsonParkCusterCascadeMeagherMusselshellFergus
Big Horn as created in 1913Where its land was the day beforeToday's boundaryBoundaries: Newberry Library, Atlas of Historical County Boundaries

Records stay with the county that created them. If your ancestor lived here before 1913, search the parent county. The Atlas of Historical County Boundaries shows each boundary change.

Research tip

Montana began statewide registration of births and deaths in 1907. Before 1864 its land was part of Idaho, Dakota, Washington and other territories.