Wyoming Was Once Part of Mexico
Cinco De Mayo marks the anniversary of the Battle of Puebla, where Mexico manhandled a much larger French army. Although present-day Wyoming was already a United States Territory in 1862, nearly 10 percent of land in the Cowboy State was once a part of Mexico.
At one point, Wyoming was part of four countries. Although it has never been officially marked, the international border for each country likely converged somewhere near the four corners of present-day Carbon, Fremont, Natrona, and Sweetwater counties.
Most of what would later become our state was acquired by the United States from France with the Louisiana Purchase in 1803.
In 1824, Mexico defeated Spain and claimed land in south-western Wyoming
When the Republic of Texas won its independence from Mexico in 1836, they claimed a small portion of Wyoming.
In 1846, England officially surrendered the Oregon Territory to the United States, which included areas in the northwestern corner of Wyoming.
The United States annexed Texas in 1844, which included their land holdings in the Cowboy State.
Finally, in 1848, following the Mexican-American War and the Treaty of Guadalupe, all of the land that would eventually become Wyoming was under United States control.