Changes

During his tenure, U.S. President [https://www.amazon.com/gp/product/0812976746/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0812976746&linkCode=as2&tag=dailyh0c-20&linkId=69a3bd8f0ab5dd2a0c0838d2b5ba9c81 James K. Polk] oversaw the greatest territorial expansion of the United States to date. Polk accomplished this through the annexation of Texas in 1845, the negotiation of the Oregon Treaty with Great Britain in 1846, and the conclusion of the [https://www.amazon.com/gp/product/0674972341/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0674972341&linkCode=as2&tag=dailyh0c-20&linkId=9e0b1045b3d7ff8e6f91ab801fbbc5a3 Mexican-American War] in 1848, which ended with the signing and ratification of the Treaty of Guadalupe-Hidalgo in 1848.