For most of us, it is hard to realize how recent was the time when the western half of the present United States was not a part of this nation. In 1845, the United States had only a claim to the Pacific Northwest.  The present states of California, Arizona New Mexico, Utah, Nevada and most of Colorado were Mexican territory. The present state of Texas was an independent republic, which had constant land issues with Mexico.

Within two years, in the administration of President James K. Polk, the British were out of the Oregon country and the present Northwestern boundary had been established. The hold of Mexico on California and the Southwest had been replaced by United States possession and the Republic of Texas had become a state of the Union.

This expansion came at the expense of the War with Mexico, with the invasion from the North by Brigadier General Zachary Taylor, Old Rough and Ready, under the command of Major General Winfield Scott, who also led America’s first D-day invasion of 10,000 U. S troops, via the United State Navy, on the shores of Mexico below Vera Cruz, fighting through and occupying the “Halls of the Montezumas” on September 14, 1847, thus mainly ending the two year war.  

Treaty With Mexico

In February 1848, the Treaty of Guadalupe Hidalgo was signed, and ratified in May, confirming the Rio Grande up to El Paso and a line drawn thence to the Pacific Ocean as the boundary between the United States and Mexico.  The War with Mexico added the immense Southwest, another result that no one until this day would undo. The Mexican War was a small affair by modern standards of combat, but it was a war with big consequences. 

To Mexico the war meant finally giving up its claims to Texas and its hold on California, and losing its outpost of New Mexico, but it meant the nation was finally established.

To the United States, the war meant new territory and new problems, one of which, slavery being pressured upon the new territories, which eventually led to this nation’s next war, the Civil War.  It should be noted that not one square mile of the new territory added to the United States was opened to slavery.

To the world, the Mexican War meant that the United States was rounded out to truly continental proportions, thereby precluding any possible further European occupation of territory on the American continent.  The War with Mexico was an inglorious step in the history of the United States, which made us what we are today in the world, a powerful nation from sea to shining sea.

References taken from the writings of Historian, Robert Selph Henry, Author, The Story of the Mexican War.