By international agreement. They may include physical landmarks such as rivers or mountains.
by the mountains,rivers.allys, and other
all the above
Idaho's eastern border is defined by the rocky mountains.
Scotland and England share a common border.
GuatemalaBelize
Mexico/Canada
France and Germany
France and Germany
Tables
The southern border of Ohio is 981 miles and is defined by the Ohio River. It is also the southern border of Indiana and Illinois.
Only one nation shares a common border with the USA's southern border: Mexico.
There are many island nations which share borders with each other. - The United Kingdom and the Republic of Ireland are both island nations and share a border with each other on the island of Ireland. - Haiti and the Dominican Republic are both island nations and share a border with each other on the island of Hispaniola. - Indonesia and Brunei are both island nations and share a border with Malaysia on the island of Borneo. Malaysia is not an island nation. - Indonesia and Timor Leste are both island nations and share a border with each other on the island of Timor. - Indonesia and Papua New Guinea are both island nations and share a border with each other on the island of New Guinea.
Lake chad and Spain