jan 1, 1848 - 1848 - The Treaty of Guadalupe Hidalgo annexed land in the Southwest. Additionally, it granted citizenship to many of the previously Mexican citizens living in the lands newly acquired by the United States in the New Mexico territory and California. This led to a demographic shift in the United States as a whole (though not in any particular region) as Hispanics became a significant population group for the first time.
Added to timeline:
Date:
jan 1, 1848
Now
~ 177 years ago