Mexico shares its northern border with the USA.
The USA is the only country which shares a land border with Canada. ================================================= Canada also shares a land border with Denmark. The international boundary runs through Hans Island, which is between Ellesmere Island and Greenland.
USA
Only one nation shares a common border with the USA's southern border: Mexico.
New Mexico shares it's long southern border with Texas.
Canada and Mexico both border the USA.
USA
The USA's longest border is with Canada.
territorial borders with russia are shared by the usa nkorea china Mongolia kazakhstan azerbaijan Ukraine belarus Latvia Estonia Finland Norway Lithuania Poland & Georgia whether including or excluding south ossetia & abkhazia territorial claims & borders with russia are disputed by japan
The USA
USA!
Canada and USA