What the western or estern of Colorado part of the purches?

The western part of Colorado was acquired as part of the Louisiana Purchase in 1803, which significantly expanded U.S. territory. The eastern part of Colorado, however, was primarily part of the land acquired through the Treaty of Guadalupe Hidalgo in 1848, which ended the Mexican-American War. Therefore, the western region aligns more closely with the Louisiana Purchase, while the eastern region has ties to later territorial agreements.