When the U.S. and Mexico Went to War

by Gerard Sanchez, age 10

Today, Mexico and the United States of America are neighbors; however, 180 years ago, they were at war.

The two countries fought over the territory between the Rio Grande and the Nueces River. Mexico declared that the border was 100 miles to the east, but the U.S. did not respect the boundary and instead claimed that Texas ended at the Rio Grande.

Texas became a state in 1845. That same year, President James K. Polk sent soldiers to the contested zone to protect Texas. When the American troops reached the Rio Grande, they started fighting with Mexican troops near Palo Alto. Five days later, on May 8, 1846, the U.S. declared war on Mexico.

The war lasted two years, with the U.S. winning most of the battles. General Zachary Taylor, who later became president, led the U.S forces. The campaign extended deep into Mexico, reaching Monterrey on September 24, 1846. A major battle took place in Buena Vista on February 23, 1847. Taylor had 4,700 soldiers while the Mexicans, led by Antonio Lopez de Santa Anna, had 20,000 soldiers. Despite the odds, the Americans won the battle and the Mexicans retreated.

As a result of the Mexican-American War, the United States significantly expanded its territory. On February 2, 1848, Mexico and the United States signed the Treaty of Guadalupe Hidalgo. Mexico accepted the Rio Grande as its boundary, and in the end, the U.S. got more territory, including Nevada, most of what is now Utah, Arizona, Colorado, and Wyoming. Mexico received $15 million as part of the treaty.

Along with gaining territory in the south, the Americans also took ownership of California over time. Commodore John D. Sloat traveled to Monterey, California, as victories were won in Mexico and took possession of the area on July 7, 1846. San Francisco was claimed the next day. By January 1847, the United States controlled all of California.

The Mexican-American War resulted in territorial changes that significantly reshaped the map of North America. The Treaty of Guadalupe Hidalgo concluded the conflict, resulting in Mexico ceding a large portion of its territory to the United States. This war was a turning point in both U.S and Mexican history, with lasting importance and impacts that are seen today.

[Source: Britannica Kids]