A border is a line that separates two countries, while a boundary is a line that separates two administrative units within a country.

Natural boundaries are formed by physical features such as rivers, mountains, and deserts, while artificial boundaries are created by humans, such as lines of latitude and longitude or political agreements.

The Rio Grande River is a natural boundary that separates the United States and Mexico.

The Mason-Dixon Line is an artificial boundary that separates the states of Pennsylvania and Maryland.

A buffer zone is an area of land that is located between two borders and is intended to prevent conflict between the two countries.

Annexation is the process of adding territory to a country.

Cession is the process of giving up territory to another country.

Redistricting is the process of redrawing the boundaries of electoral districts.

Gerrymandering is the practice of drawing electoral districts in a way that gives one political party an advantage over another.

Devolution is the process of dividing a country into smaller administrative units.

Federalism is a system of government in which power is shared between a central government and regional governments.

Unitarism is a system of government in which all power is held by a central government.

A confederation is a system of government in which a group of states come together to form a loose alliance.

Migration is the process of moving people from one country to another.

Immigration is the process of moving to a new country.

Emigration is the process of leaving a country to live in another country.

Repatriation is the process of returning to one's home country after living in another country.