What were the territorial gains for the USA post-Mexican-American War?

The USA gained over 500,000 square miles of territory following the Mexican-American War.

The Mexican-American War, which took place between 1846 and 1848, resulted in significant territorial gains for the United States. The Treaty of Guadalupe Hidalgo, signed on 2nd February 1848, ended the war and ceded a vast amount of land to the USA. This included the present-day states of California, Nevada, Utah, most of Arizona, about half of New Mexico, about a quarter of Colorado, and a small section of Wyoming. This territory, over 500,000 square miles in size, represented a significant expansion of US territory.

The war began due to a dispute over the border between Texas, which had recently been annexed by the USA, and Mexico. The USA claimed the border was the Rio Grande, while Mexico insisted it was the Nueces River, further to the north. When a skirmish broke out between American and Mexican troops, the USA declared war. The war was controversial, with many in the USA, particularly in the North, seeing it as an attempt to expand slave territory.

The war was largely fought on Mexican soil and resulted in a decisive American victory. The Treaty of Guadalupe Hidalgo not only ceded territory but also recognised the Rio Grande as the border between Texas and Mexico. In return, the USA agreed to pay $15 million to Mexico and assume $3.25 million of debt owed by the Mexican government to American citizens.

The territorial gains from the Mexican-American War had a profound impact on the USA. It fulfilled the idea of 'Manifest Destiny', the belief that the USA was destined to stretch from coast to coast. However, it also exacerbated tensions between the North and South over the issue of slavery, as it raised the question of whether slavery would be allowed in the new territories. These tensions would eventually contribute to the outbreak of the American Civil War.