The island had air fields the the u.s military needed.
The treaty of Guadalupe-Hidalgo gave the United States some territory <u>south of the Rio Grande</u>
Explanation:
The treaty of Guadalupe-Hidalgo signed between the United States and Mexico on February 2, 1848, led to a territorial exchange of lands between the two parties.
Mexico had to surrender Texas state and accept the Rio Grande as the boundary of Texas state. This led to half the size of Mexico and increase the size of the United States with a bountiful of rich natural resources.
This increase of vast land tract to the United States included many regions from California to Kansas for which the US paid $15 million.
The Rio Grande is part of the territorial boundary shared by the United States and Mexico.
