The state of Montana was once home to a massive inland sea that covered much of North America around 80 million years ago during the Late Cretaceous period.
Powder River County, located in southeastern Montana, has a rich history dating back thousands of years. The area was originally inhabited by various Native American tribes, such as the Cheyenne and Sioux. These tribes relied on the abundant wildlife and natural resources of the region for sustenance and trade.

In the 19th century, European settlers began to arrive in Powder River County. The discovery of gold in nearby cities like Deadwood, South Dakota spurred an influx of prospectors and miners into the area. This led to the establishment of several towns, including Broadus, the current county seat, in 1901.

A significant event in Powder River County's history was the outbreak of the Northern Cheyenne Exodus in 1878. Seeking to return to their ancestral homeland in the north, the Cheyenne people embarked on a perilous journey across the Great Plains, passing through the county. Their struggle for land and freedom is an integral part of the county's history.

During the late 19th and early 20th centuries, Powder River County was primarily an agricultural region, with ranching being the main industry. Cattle and sheep ranching flourished, as the vast grasslands provided ample grazing opportunities. Today, ranching still plays a crucial role in the county's economy, along with oil and gas development.

Despite its rural nature, Powder River County has seen various changes and developments over the years. Improved transportation, such as the construction of highways and railroads, has facilitated economic growth and connectivity with surrounding areas. Today, the county remains a picturesque and historically significant part of Montana, retaining its rural charm and serving as a reminder of its storied past.

This timeline provides a concise overview of the key events in the history of Powder River County, Montana.

  • 1879: Powder River County was established on February 7, 1879.
  • 1882: The 1882 census showed a population of 10 people in Powder River County.
  • 1884: The first post office in the county was established on April 4, 1884, in Broadus.
  • 1900: The population of Powder River County grew to 588 people.
  • 1914: The first courthouse was built in Powder River County.
  • 1919: The Powder River County fair was held for the first time.
  • 1920: The population of Powder River County reached 3,219 people.
  • 1926: The official Powder River County newspaper, the Powder River Examiner, was first published.
  • 1940: The population of Powder River County reached its peak at 6,865 people.
  • 1967: Powder River County Museum was established in Broadus.
  • 1989: The Powder River County Library was completed.
  • 1991: Total land area of Powder River County was 3,298 square miles.
  • 2000: The population of Powder River County was 1,858 people.