Top level domains differences.

[SAguy]

Why do some countries have a top level domain of google.com.ng (Nigeria) whereas other countries have google.co.za (South Africa). Furthermore, other countries just have google.cd (DRC).

Other countries have two different TLD's. Like Mauritius has co.mu as well as just .mu.

 

[RoganDawes]

As far as I understand it, each country was assigned their TLD, and then their own internal structures decided how to slice it up.

Some looked at what others were doing, and followed along, some did their own thing. Hence the inconsistencies.