the Rio Grande.
The Rio Grande, Spanish for grand river, forms the southern border of the United States, but it only forms the border between Texas and Mexico. New Mexico is not bordered by the Rio Grande, for example, but rather the Rio Grande runs through New Mexico.The only river that partially forms the southern border of the U.S. is the Rio Grande on the Texas/Mexico border.The rest of America's souther border with Mexico is a land border in souther New Mexico, Arizona, & Colorado.
The Columbia River
Columbia River
columbia river
The Columbia River
The Columbia River
The Columbia River
The Columbia River
The Columbia River borders most of the length between Washington & Oregon.
The Columbia River forms part of the border between Washington State and Oregon. Both of these states are West of the Mississippi River.
The Potomac River forms part of the border between Washington D.C. and Maryland.