Petroleum County, Montana History and Genealogy

Part of the MTGenWeb and USGenWeb Projects
The Rimrocks on the east edge of Winnett, Montana the county seat. © Ann Kramlich
Established in 1925 from Fergus County County Seat, Winnett

This website is available for adoption.
If you are interested, please contact the MTGenWeb State Coordinator

As of the 2010 U.S. Census, there were 494 people in Petroleum county. This makes Petroleum county the least populous in Montana and one of the least populous in the United States. Petroleum county has an estimated 511 people in the 2012 U.S. Census.

Petroleum county was created on February 25, 1925 and was the last of Montana's 56 counties to be created. It was named Petroleum because of the petroleum being extracted from Cat Creek Oil Field. Oil was discovered on February 18, 1920.

The county seat of Winnett is named for Walter John Winnett, who was a Canadian rancher captured by the Sioux and later adopted into the tribe. His Sioux name was Eagle Eyes due to his excellent shooting skills. Winnett started a ranch in Montana Territory in 1879 near an active trading post along McDonald Creek and the Hangman's Tree used by vigilantes in the area. He built the ranch house in 1900 and besides being a home for his family, it was also a meeting place for the community. Winnett also built a freight business to haul supplies from Billings and in 1910 he built a store and petitioned for a post office. Then, Winnett became an official town.

If you are looking for someone who may have been in Petroleum County before 1925, you would need to research records in Fergus County.

Homestead Shacks over Buffalo Tracks, a History of Northeastern Fergus County Covers part of Petroleum County area. Permission was granted by the Roy Genealogy and History Committee to transcribe and post this history of Roy on the MtGenWeb Project site. Very good reading and many interesting family histories.
Surname Index for Homestead Shacks over Buffalo Tracks

Pages of Time, A History of Petroleum County, Montana By the Petroleum County Public Library 

Vigilantes of Montana

Boulden's Retire from Mosby Post Office Plaque

Petroleum County Cemeteries Includes Photos.
ATTN: Most of these cemeteries are on private property. Please obtain consent and make arrangements to visit the cemeteries before just showing up and driving through the landowners fields. Thank you!

Ashley Cemetery Northeast of Winnett on private property.
Flatwillow Cemetery South of Winnett just off the highway.
Shay Cemetery East & North of Winnett
Wallview Cemetery South of Winnett near the Musselshell County Line.
Winnett Cemetery Across the highway north of Winnett.
Miscellaneous Cemeteries - Petroleum County, some but not all small private cemeteries around the county.

Cemeteries -- USGS National Mapping Information
Petroleum County Historical Forts And Camps -- USGS National Mapping Information
Petroleum County Populated Places -- USGS National Mapping Information

Petroleum County National Register of Historic Places

Montana Genealogy Society
Montana Historical Society
Montana Native Americans
Montana State Homepage

Surname Helper

Lookups --Volunteers that have offered to lookup information in books or on CD's they own.

Descriptions and subscribing information can be found by following the URL's linked to the list names below:

Message Boards -- these may assist with your research
Petroleum County message board
Fergus County message board
Métis message board
Montana Unknowns message board

Montana First Families

Military: Montana
World War I Search by state for information of service and burial location
World War II Search by state for information of service and burial location
World War II Honor list of dead and missing Army and Army Air Forces Personnel

World War II Casualties Navy, Marine Corps and Coast Guard Personnel
Korean War Search by state for information of service and burial location
Korean War Alphabetical by Surname
Korean War By Hometown of Record
Vietnam Alphabetical by surname
Vietnam By Hometown of Record

Montana Photo Archives --Old and new photos submitted by MTGenWeb Volunteers and many very special friends of the MTGenWeb Project. Super photo history of Montana

Winnett High School Graduates

Neighboring Counties --Links to counties bordering Petroleum County
Fergus County
Garfield County
Musselshell County
Phillips County
Rosebud County

Post Offices --USGS National Mapping Information
Schools-- USGS National Mapping Information



Petroleum County Community Library

P.O. Box 167
Winnett, Montana 59087

Pages of time : a history of Petroleum County, Montana

Family History Files  A-E F-K L-R S-Z
Files for Communities, Photos, Documents, Maps and more

Lewistown (Fergus County) Public Library
701 W Main St,
Lewistown, Montana
Telephone: (406)-538-5212


Central Montana Genealogy Society

You will find their link at the bottom of the Library Page,
located upstairs at the Library.


Billings Gazette Online
Vitals online Since June 98
P.O. Box 36300
Billings, Montana 59107
Phone: 406-657-1200

Roundup Record Tribune & Winnett Times
24 Main
Roundup, Montana 59072
Phone: 406-323-1105

Lewistown News Argus
P.O. Box 900
521 W. Main
Lewistown, Montana 59457
Phone: 406-538-3401

Petroleum County Courthouse
Petroleum County Clerk of Court
201 East Main Street
Winnett, Montana 59087
Petroleum County Clerk and Recorder
201 East Main Street
Winnett, Montana 59087

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updated April 4, 2019

Pages maintained by Petroleum County Coordinator