The Mississippi river
Pacific
Mississippi River
The river is the Mississippi river
It is the western boarder of the State of Wisconsin.
It was the Land Act of 1800.
The Mississippi River. in 1783 Spain still had control of everything west or south of the Mississippi river including Florida and the Gulf of Mexico.
Canada
No country borders the US to the west. The western border of the US is the Pacific Ocean.
The US, Mexico and perhaps Cuba.
Since Mexico and the US share a boarder, technically the distance from Mexico to the US is zero.
In the mid 1800's
New England on the coast. Mass., RI, and NY boarder it.