Have you ever wondered how Colorado and much of the American West became part of the United States?  Well, there was this war.  The loser of the war had to agree to give up something.  The loser agreed to give up a huge amount of land.  That land was Colorado and a large area that included what is now Texas, New Mexico, Arizona, Nevada, California, and Utah.

The winner?  You guessed it: the United States of America.  The loser?  Very good…you guessed that too: Mexico.  The agreement for all the land?  It was: the Treaty of Guadalupe Hidalgo.

Mexico had been an influence in the region for hundreds of years.  Spain added its influence to Mexico in the early 1500’s.  Britain and Mexico started to cross paths with each other long before the United States of America declared its independence in July 1776.  As part of its struggle to survive and grow, the USA was frequently at odds with Mexico.

In 1803, President Thomas Jefferson, purchased the territory of Louisiana from Napoleon and France for $15 million.  (Napoleon wanted the money to help finance his wars with Britain and its European allies.) This motivated the young United States to look west for growth.  It also put Mexico on the defensive.

To aid in its claim on the west, the United States encouraged people from all over Europe to emigrate and settle in the west.  A big part of that was Texas, also a territory claimed by Mexico.  Social and economic friction started to become open conflict.  In April 1836, Mexican and Texan armies battled each other at the Alamo, an old Spanish mission, in San Antonio, Texas.  Nearly 200 Texan fighters were killed.  To say the battle left a lasting impression is an understatement. (The Mexican Army did not spare a single Texan fighter.)

Ten years later, Mexican and American armies faced each other again.  This time it was at place called Rancho de Carricitos, not far from present-day Brownsville, Texas. The US wanted the territory of Texas.  Mexico did not want to give it up.  As fights like this go, one side provoked the other and bullets started to fly.  Fourteen American lives were lost.  Polk, the US President at the time, declared war on Mexico.

In January 1848, American forces entered Mexico City and took control.  An agreement was written to formally end the Mexican-American War.  It was called the Treaty of Guadalupe Hidalgo.  (At the time, Guadalupe Hidalgo was a village outside of Mexico City.)  For its part, Mexico would give the United States the land that included: Texas, New Mexico, Colorado, Utah, Nevada, Arizona, and California.  The United States agreed to pay $15 million for this land.   (It’s interesting to note that $15 million then would be worth over $500 million in today’s dollars.)  The United States also agreed to settle any claims that Mexican citizens had against the US. The treaty was signed on February 2, 1848.

The Louisiana Purchase got America the middle and northwestern parts of the country.  The Treaty of Guadalupe Hidalgo got America the remainder of the West.