Shifting Boundaries, 1823–1854
CHAPTER EIGHT CONSIDERS HOW, BEGINNING IN THE 1820S, a flood of settlers came from the United States to Texas, then a part of northern Mexico. These settlerssome arriving legally and some illegally-became the dominant population group. Resent - ment against Mexican control built up, leading to a successful rebellion in 1836. The chapter then considers how the United States annexed Texas, which had existed as an independent republic for nine years. Shortly after annexation U.S. Present Polk ordered troops south of the Nueces River-historically the southern boundary of Texas. Combat between U.S. and Mexican forces soon erupted, giving the United States a causa belli. American troops then drove deep into northern Mexico, marched west to California, and after an amphibious landing at Vera Cruz, fought their way inland to Mexico City. To end hostilities, the two nations signed the Treaty of Guadalupe Hidalgo, which ceded to the United States territory which became the states of New Mexico, Arizona, and California.