The cause of the Treaty of Guadalupe Hidalgo was the fact that Mexico's capital had fallen and the army had been defeated, so Mexico entered negotiations with the United States. The Treaty of Guadalupe Hidalgo is also known as the friendship treaty between the United States and Mexico. The effect of this treaty ended up with the United States gaining the Rio Grande in Texas, California, parts of New Mexico, Nevada, Utah, Wyoming and Colorado. The Mexicans in this area had the choice of relocating or receiving full American citizenship. Ninety percent of Mexicans chose to receive American citizenship.
