What war happened after Texas became a state?

After Texas became a state in 1845, the Mexican-American War occurred from 1846 to 1848. The conflict arose primarily from territorial disputes following Texas's annexation, as Mexico still considered Texas part of its territory. The war ended with the Treaty of Guadalupe Hidalgo, which resulted in the U.S. acquiring significant territories, including present-day California, Arizona, New Mexico, and parts of Colorado, Nevada, and Utah.