In 1848, after the Mexican–American War, the Treaty of Guadalupe Hidalgo with Spain brought into the United States all or part of land for ten future states, including southwest Kansas.
The transfer of land from Spain to the United States in 1848, following the Mexican–American War, had significant implications for the country's expansion and growth. The Treaty of Guadalupe Hidalgo led to the inclusion of southwest Kansas as part of ten future states, shaping the region's history and development.