New Mexico was one of the last territories to become a state, gaining statehood in 1912. Before that, it had been part of the Spanish Empire, Mexico, and the United States Territory of New Mexico.
Union County, located in northeastern New Mexico, has a rich history that spans over centuries. The area was originally inhabited by Native American tribes, including the Ute, Comanche, and Apache. Their presence can still be seen in the numerous archaeological sites found in the county.

The history of Union County is entwined with the expansion of European settlers into the area. In the mid-1800s, the Santa Fe Trail passed through this region, leading to an increase in trading, and eventually the establishment of small communities. However, it was not until 1893 when Union County was officially formed, named after the ideal of unity between settlers and indigenous populations.

The late 19th and early 20th centuries saw significant growth in Union County, largely driven by the discovery of coal and the construction of the AT&SF Railroad. The coal industry boomed, attracting miners and their families to towns like Dawson and Folsom. However, the coal mines eventually declined, leading to a significant population decrease and economic challenges.

In recent decades, Union County has focused on diversifying its economy. Tourism has become an increasingly important industry, thanks to the area's natural beauty and attractions such as the Capulin Volcano National Monument and Mills Canyon. Agriculture, particularly cattle ranching, also plays a crucial role in the county's economy. Today, Union County continues to preserve its history while looking towards the future with a growing focus on sustainable development and community revitalization.

This timeline provides a glimpse into the major events and milestones that have shaped the history of Union County, New Mexico.

  • 1869: Union County is established as a county in the Territory of New Mexico.
  • 1876: The Santa Fe Trail, a major trade route, passes through Union County.
  • 1885: The railroad reaches the town of Folsom, contributing to its growth.
  • 1908: Folsom Man, ancient human remains, are discovered near Folsom, providing significant archaeological findings.
  • 1912: New Mexico becomes a state, and Union County is part of the Union.
  • 1920s: Rapid growth in mining and agriculture sectors boosts the county's economy.
  • 1948: The town of Clayton is officially incorporated, becoming the county seat.
  • 1950s: The discovery of natural gas leads to increased drilling and economic development.
  • 1997: Vermejo Park Ranch, a large conservation area, is established in Union County.
  • 2006: The Philmont Scout Ranch, a popular destination for Boy Scouts, celebrates its 75th anniversary.