How many countries in North America have a border with South America?

23 countries in North America have a border with South America.

Explanation:

It has an overland border with the continent of South America which runs along the Panama-Colombia state boundary. In total there are 23officially recognized sovereign states in North America.At some point, the boundary between North America and South America falls on Panama's Isthmus. The most famous demarcation in atlases and other documents parallels the dividing watershed of the Darién Mountains along the Colombia-Panama border where the isthmus meets the continent of South America.

Answer after wwii, communist countries in eastern europe formed the warsaw pack, a military alliance, and comecon, an economic alliance;