Which nation signed a treaty in 1848 that granted the U.S. extensive territory following a war?

The treaty signed in 1848 that granted the United States extensive territory was the Treaty of Guadalupe Hidalgo, which was an outcome of the Mexican-American War. This treaty significantly expanded U.S. territory, acquiring lands that include present-day California, Nevada, Utah, Arizona, and parts of Colorado and New Mexico.

The U.S. fought against Mexico from 1846 to 1848, and the war stemmed from issues including the annexation of Texas, which Mexico still considered part of its territory. The signing of the treaty formalized the end of hostilities and delineated the new borders, marking a pivotal moment in U.S. history as it contributed to the notion of Manifest Destiny—the belief that the U.S. was destined to expand across the North American continent.

Other nations listed did not sign treaties that resulted in similar territorial gains for the U.S. during this timeframe. For example, Spain had earlier ceded Florida to the U.S. in 1819, while France sold the Louisiana Territory in 1803, and Great Britain settled various land disputes with the U.S. through treaties in the early 1800s, but none of these events occurred in the context of a war fought in the 1840s