The mexican war began in and was the first war the united states fought mostly on foreign soil. the tensions between the u. s. and mexico centered around the territory of texas. presidents- including andrew jackson and - had not want to add it as another state since it would likely enter the country as a state, upsetting the balance of power in congress. but in 1844, president urged congress to declare war on mexico after that country refused to agree to sell texas to the u. s. by the time the war finally broke out, the u. s. had texas anyway.

fighting took place in a number of areas. in june of 1846, major led a small force to overthrow mexican rule in northern california. this was the independent so-called . weeks later, general stephen kearney led his troops to capture the capital of the new mexico territory, . general zachary taylor led over 6,000 troops deep into the heart of mexico, while general winfield scott took nearly 15,000 men and seized the coastal town of . by september of , the capital of mexico city was taken by u. s. forces and the fighting came to an end.

the war officially came to an end with the treaty of on five months later in february of . the treaty held that mexico would recognize the as the southern border of texas, the u. s. would take possession of and new mexico, a deal that became known as the