In Northern California, a small group of Americans overthrew the Mexican government with a small war against the Mexicans. This was known as the, "Bear Flag Revolution". To symbolize their successful insurrection, they carried around a flag that showed a grizzly bear facing a red star.
Face it! I'm going to overthrow your government!
Nooooo!
General Kearney's Army took surprise by a large force of Mexican soldiers, the Californios. They battled until Kearney's troops treated to a small pile of rocks where they were able to hold them off a little easier. This is where the soldiers had to eat mule to keep themselves from starving, and these small pile of rocks were now known as, "Mule Hill."
Retreat! Retreat! Fall back everyone! Head toward the small pile of rocks!
Fire! Fire! Fire!
After many series of battles, General Winfield Scott and his troops made their way into Vera Cruz and demanded a surrender after the Battle of Buena Vista, but, Santa Anna didn't accept. However, the Mexican troops were tired of fighting and wanted Santa Anna to resign as president, so, the new Mexican government just accepted the American demands anyway. And, the Treaty of Guadalupe Hidalgo finally ended the war.