How did texas become part of the united states?

Mexico controlled the territory until 1836 when Texas won its independence, becoming an independent Republic. In 1845 it joined the United States as the 28th state. The state's annexation set off a chain of events that caused the Mexican–American War in 1846.

Texas was originally owned by Mexico. The United States government desired the piece of land planning to accomplish Manifest Destiny. The Mexican-American war took place in order to own the land, and the Texas was soon liberated.