The closest place to the southern US border is Mexico, which happens to be in North America, just like the US is. The continent that borders North America is South America.
Border? It is on the southern US border.
The Country that shares the southern Border with the US is Canada.
The southern border of the US is primarily located along the countries of Mexico.
Mexico is the country on the southern border of the United States.
The US state of South Dakota is the southern border of North Dakota.
The United States is closer to the equator.
Rio Grande forms the Southern border of the United states.
The U.S. southern border is formed by Mexico and the Gulf of Mexico.
Northern border is Canada Southern border is Mexico
Southern Spain is closer by a few hundred miles to Illinois. Some locations in the southern and western US are closer to Argentina.
Mexico
Mexico