Which of the following groups was most immediately affected by the Gadsden Purchase?

It was the Gadsden Purchase that settled the main boundaries of the United States of America. The federal government went on to expand the borders by diplomacy, purchase, annexation and war. The purchase included lands south of the Gila River and west of the Rio Grande; it was largely so that the U. S. A. could construct a transcontinental railroad along a deep southern route.

Florida was mopped up in 1819. In 1836 the American settlers in Texas threw off the yoke of Mexico and declared their independence.