Mexican-American War 1846

Why did the war take place?

The war took place over the issue of Texas. In the 1830s, American settlers in Texas fought against Mexican rule and declared independence from Mexico. Mexico was defeated and continued to claim its right over Texas. So when U.S. Congress agreed to make Texas the 28th state of U.S.A., Mexicans were angry.

Another major reason was the disagreement over the border of Texas. The Mexican government said that the Texan border ended at Nueces River. The Texans claimed that their border went all the way until the Rio Grande River. It was finally to settle this border dispute that both sides came to war.

Battle of Palo Alto 1846

The Battle of Palo Alto took place near Brownsville, Texas Read more about the Battle of Palo Alto 1846 >>

Battle of San Jacinto

Texans didn't want to be ruled by Mexico. Most of the Texans were white settlers from USA Read more about the Battle of San Jacinto >>

Battle of the Alamo

Alamo was the name of the fort in San Antonio Texas, built by Spanish soldiers Read more about the Battle of the Alamo >>

Sam Houston

Sam Houston was one of the most important leaders of Texas at the time when Texas revolted against Mexican rule Read more about the Sam Houston >>

Texans defeat Mexican Army

The Texan army included famous fighters such as James Bowie Read more about the Texans defeat Mexican Army >>

Texas Independence

The Battle of the Alamo was one of the most famous events of the Texas Revolution Read more about the Texas Independence >>

Texas Joins USA – 1845

Until the 1820s, the whole of Mexico including Texas which was then a part of Mexico Read more about the Texas Joins USA – 1845 >>

Treaty of Guadalupe Hidalgo

The Treaty of Guadalupe Hidalgo was signed on February 2 1848 Read more about the Treaty of Guadalupe Hidalgo >>

U.S. Captures Mexico City 1847

American forces started their attack on Mexico City on September 8, 1847 Read more about the U.S. Captures Mexico City 1847 >>

The Beginning of the War

The Mexican-American War began on April 25, 1846. American government sent an army under General Zachary Taylor to reach the Texan border and stop any Mexican army from crossing the Rio Grande River. Mexico responded by sending its own army which crossed the Rio Grande River and attacked the American fortifications.

This led to the battles of Palo Alto and Resaca de la Palma, both of them the earliest proper battles in the war. The Mexican army was defeated in both wars and was forced to retreat beyond the Rio Grande River, back into the Mexican territory.

American forces enter Mexico

After defeating the Mexican army on this side of the border, the American army crossed the Rio Grande River and entered Mexico. Its purpose was to force the Mexican government to accept the Texan independence and to agree the Rio Grande River as the official border.

The Mexican government, on the other hand, braced for a defensive war and said that the American forces were encroaching on Mexican territories. So the war continued, now taking place inside Mexico. A number of battles were fought and the Mexican army lost most of them, eventually also losing control of many important cities. These include Monterrey and the capital of Mexico, the Mexico City.

Negotiations for Peace

After losing most of the battles during the war and finally losing control of the Mexico City in 1847, Mexico realized that it could not possibly win the war. The American government also wanted to end this military conflict which had gone on for long enough. So both sides decided to negotiate for peace. These negotiations finally resulted in peace treaty signed by both sides in February, 1848. This was called the Treaty of Guadalupe Hidalgo. The treaty was ratified in May 1848, effectively bringing the war to an end.


Mexico was forced to recognize the Rio Grande River as the official border between U.S.A and Mexico. Mexico also gave up a huge portion of its northern territories which include modern-day states of New Mexico, Utah, California, Arizona and Colorado as well as parts of Wyoming and Kansas. In return, U.S. government paid $15 million for the acquisition of these territories. Following the conclusion of peace, the American army returned to the U.S. territories, handing back the control of the conquered land to the Mexican government.

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