AMSCO AP United States History Exam (APUSH) 2025 – Free Period 5 Practice Test Questions and Study Guide

The correct answer is based on the historical context of the border dispute between the United States and Mexico in the mid-19th century, specifically during the lead-up to the Mexican-American War. The dispute primarily revolved around the location of the southern boundary of Texas after it was annexed by the U.S.

The Nueces River, which flows through Texas, was claimed by Mexico as the border, while the United States asserted that the Rio Grande should be the boundary. This disagreement over river boundaries became a significant point of conflict, ultimately leading to military engagement and the subsequent war. The resolution of this dispute, along with the Treaty of Guadalupe Hidalgo, established the Rio Grande as the recognized border between the two nations.

Other pairs of rivers listed do not pertain to this specific conflict. The Mississippi and Missouri Rivers are major waterways but do not relate to the U.S.-Mexico border issue. The Columbia and Ohio Rivers are geographically distant from each other and unrelated to the border conflicts. The Rio Grande and Colorado Rivers, while they are both significant rivers in the West, were not the focus of the boundary dispute discussed in relation to Texas and Mexico.