Blaine County, Montana Genealogy Records

Selected record inventories for Blaine 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
1912
County seat
Chinook
Broadwater CountyCascade CountyDeer Lodge CountyFergus CountyFlathead CountyGallatin CountyGarfield CountyGlacier CountyGolden Valley CountyHill CountyJefferson CountyJudith Basin CountyLewis and Clark CountyLiberty CountyMeagher CountyMusselshell CountyPark CountyPetroleum CountyPhillips CountyPondera CountyPowell CountyRosebud CountySilver Bow CountyStillwater CountySweet Grass CountyTeton CountyToole CountyTreasure CountyValley CountyWheatland CountyYellowstone CountyChouteau CountyBlaine CountyCascadeFergusFlatheadGarfieldGlacierHillMeagherPhillipsPonderaPowellTetonTooleValleyChouteauBlaine
Blaine CountyParent county (search here for earlier records)Today's boundaries ยท U.S. Census Bureau

Listed record inventories

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

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

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

Boundaries and parent counties

Formed from: Chouteau County

Check the parent county for earlier records: Chouteau County

Later formed partly from Blaine County: Phillips County

GallatinGraniteDawsonTetonValleyParkSweet GrassRosebudJeffersonDeer LodgePowellSilver BowLewis And ClarkCascadeFlatheadBeaverheadBroadwaterYellowstoneMeagherMusselshellFergusHillChouteauBlaineBlaineChouteauDawsonTetonValleyPowellCascadeFlatheadMeagherMusselshellFergusHill
Blaine as created in 1912Where 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 1912, 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.