1. Annexation of Texas by the United States: Texas, which had declared independence from Mexico in 1836 and was later annexed by the United States in 1845, became a state of the United States.
2. Rio Grande as the Boundary: The treaty established the Rio Grande as the official boundary between the United States and Mexico. The southern border of Texas was defined by the course of the Rio Grande from El Paso in the west to the Gulf of Mexico in the east.
3. Loss of Territory: As part of the treaty, Mexico ceded a vast amount of territory to the United States, including the present-day states of California, Nevada, Utah, Arizona, and parts of Colorado and New Mexico. This resulted in the loss of significant territory for Mexico along its northern border with the United States, including areas that had previously been part of northern Mexico.
4. Population Transfers: The treaty required that Mexican citizens living in the newly acquired territories could either choose to remain in their homes and become citizens of the United States, or they could return to Mexico. Many Mexicans chose to remain in the United States and became American citizens.
5. Economic and Cultural Impact: The influx of Mexican-American settlers into the southwestern United States and Texas brought new cultural influences, languages, and customs to the region. This had a profound impact on the development and identity of Texas and shaped its unique blend of Mexican and American heritage.
6. Ongoing Border Disputes: Despite the establishment of the Rio Grande as the boundary, there have been ongoing disputes and tensions over the border between the United States and Mexico, including issues related to immigration, drug trafficking, and other cross-border activities.
Overall, the Mexican War and the Treaty of Guadalupe Hidalgo had a major impact on the southern border of Texas, reshaping its political and geographical boundaries, and influencing its cultural and demographic composition.